With the launch of the Apple iPhone 5, a legion of excellent Android handsets, and the rise of Microsoft's Windows Phone 8 operating system, choosing the right smartphone has never been more difficult.

On the bright side, all these options mean greater choice, which is a good thing -- if you're armed with the knowledge necessary to make smart shopping decisions. Sit tight as we break down what you need to know to choose the right mobile platform and model to fit your needs.

Now, CNET hasn't fully reviewed every phone listed below (some aren't yet available), but we have gotten our hands on every single one, and know quite a bit about each handset.

We'll update the story periodically to reflect the arrival of new phones.

Which operating system is for you?

iOS, Android, and Windows Phone each have a lot to offer, and will appeal to people differently depending on what they want. If you aren't a fiercely loyal fan, a phone design could lure you to a new OS, but many people prefer to start with the platform.

iOS' strengths are its well-integrated ecosystem and fairly intuitive interface, but you're pretty much locked in to iTunes for content.

Android is much more customizable, but each carrier has its own twist, which can make it less easy to just pick up and use.

Windows Phone 8 is building in features that make for good high-end phones, and its fresh, simple interface is appealing, but power users won't find it flexible.

iOS 6, Android 4.1, Jelly Bean, Windows Phone 8 (Credit: CNET)

We didn't forget about BlackBerry OS, which is currently still stuck in a development cycle, and therefore isn't a serious contender. We expect BlackBerry-maker RIM to release Blackberry OS 10 and a new phone in 2013. RIM faces an uphill battle keeping loyal customers and gaining new ones, but we always hope to see a struggling player pull out something that'll amaze.

When choosing an Android phone, you have to think about the version of the OS. Android phones suffer from fragmentation, as carriers and manufacturers add their own software layers that sometimes get in the way of an update to the next generation. As such, we'd avoid any new phone running Android 2.3 Gingerbread or older, and stick with Android 4.0 Ice Cream Sandwich or Android 4.1 Jelly Bean. Higher-end phones are typically the ones to receive OS updates first.

We'd also skip Windows Phone 7 devices in favor of Windows Phone 8 for most users; Windows 7 phones won't receive many meaningful software updates from now on.

iPhones have the advantage of receiving the same OS upgrade at the same time, and the newest OS is usually available on multiple devices. iOS 6, for instance, will work on the iPhone 5, iPhone 4S, and iPhone 4, but not on the iPhone 3GS or earlier.

Best iPhone: Of those we've fully reviewed, the iPhone 4S is best, but we think that the forthcoming iPhone 5 is sure to beat it.

Best Android phones: Samsung Galaxy S3 (on five carriers), HTC One X (AT&T), HTC Evo 4G LTE (Sprint)

Best Windows Phone devices: Nokia Lumia 920 (forthcoming), Samsung Ativ S (forthcoming)

Do you shop by phone or by carrier?

If you're happy with your carrier, or if you're within an upgrade window, you'll probably pick from your carrier's choices. However, if you're off-contract or in between contract cycles, the world is your oyster.

Things you have to consider include: contract or no contract, a small data plan or a large one, and which carrier covers your area best.

National and regional carriers sign you on for a two-year contract, have a strong retail presence, and offer phones at a subsidy (hence cheaper). They also typically have the widest coverage and the lowest up-front costs, and offer premium phones.

However, every national carrier also has a prepaid option. Some, like, T-Mobile and AT&T, offer a different, usually cheaper, range of phones. Verizon lets you buy nearly any phone at retail value and then pay month-to-month. Sprint manages prepaid options through its Virgin Mobile and Boost Mobile brands. Depending on how you use the services, prepaid service could work out to be cheaper over time. You also won't have to worry about breaking your contract and paying a fee.

Six carrier logos (Credit: CNET)

Several prepaid carriers operate on their own networks as well, like MetroPCS and Cricket Wireless. These carriers have regional footprints and are sometimes slower to adopt premium phones and improve on their technology. MetroPCS was first with LTE, but its network is much slower and its coverage area is smaller. Cricket doesn't have 4G, but it does offer a unique music service.

U.S. Cellular is a regional network with both prepaid and postpaid options. There are many more carrier services as well. Get to know them better here.

Voice and data coverage are also key. There are carrier maps you can look at to see roughly if your area is taken care of, but asking neighbors is usually more reliable. All carriers are still rolling out 4G LTE networks, but Verizon is far ahead of the others. Sprint has the smallest number of markets, currently, and T-Mobile is using the pretty fast HSPA+ for 4G.

The carrier's pricing structure is also something to think about. Verizon and AT&T have pooled data plans that could be better or worse for you or your family, but AT&T's aren't mandatory for existing customers. Sprint continues to offer an unlimited data plan, and T-Mobile recently introduced its own version.

Favorite AT&T phones: HTC One X, Samsung Galaxy S3, Pantech Burst, Apple iPhone 5 (forthcoming)

Favorite Boost Mobile phones: Samsung Galaxy S II 4G, HTC Evo Design 4G, LG Rumor Reflex, Kyocera Hydro.

Favorite Cricket Wireless phones: HTC One V, Huawei Ascend II, Apple iPhone 5 (forthcoming)

Favorite MetroPCS phones: LG Motion 4G, Samsung Galaxy Attain 4G, Huawei Activa 4G

Favorite Sprint phones: HTC Evo 4G LTE, Samsung Galaxy S3, Motorola Photon Q, Apple iPhone 5 (forthcoming)

Favorite T-Mobile phones: Samsung Galaxy S3, HTC One S, Samsung Galaxy Note

Favorite U.S. Cellular phones: Samsung Galaxy S3, Motorola Electrify 2, HTC One V

Favorite Verizon phones: Samsung Galaxy S3, Motorola Droid Razr Maxx HD (forthcoming), Apple iPhone 5 (forthcoming)

Favorite Virgin Mobile phones: Apple iPhone 4S, HTC One V

Which experience: Premium or functional?

One big question to ask yourself when choosing a mobile phone is how you plan to use it. If you plan to use your phone as your primary camera; play a lot of graphically rich games; stream a lot of data; store a lot of photos, videos, e-books, and audio files; and stare at the screen for hours, then a premium smartphone is best for you.

The cream of the crop will usually have a big, high-definition screen, larger storage capacities, a higher-resolution camera, longer battery life, and a faster processor. Power doesn't come cheap, since top-tier smartphones typically run anywhere from $199.99 to $299.99, though there are promotional deals.

Samsung Gusto 2

Simple phones aren't going away.

(Credit: Josh Miller/CNET)

As nice as the premium smartphones are, for some people, they're just overkill. All the operating systems bring their software power to handsets of all shapes and sizes, which means that hardware capabilities are often the only thing that separates the tiers. If you're less picky about having the best of the best, you could walk away with a smartphone that runs all the same apps as the big boys for half the price. These phones typically cost from $0 to $150, depending on the carrier and the promotional deal.

For those looking only to text or make calls, each carrier offers messaging phones (many with keyboards) and simple phones (many with a flip design). These phones might seem pricier than you expect because the carrier isn't helping subsidize the cost, but the upside is that you won't have to fork over money for a pricey data plan each month. You can find simple phones for between $15 and $80.

Best high-end phones: Apple iPhone 5 (AT&T, Sprint, Verizon; forthcoming) Motorola Droid Razr Maxx HD (Verizon; forthcoming), Samsung Galaxy S3 (Verizon, Sprint, AT&T, T-Mobile, U.S. Cellular), HTC One X (AT&T), HTC Evo 4G LTE (Sprint), Nokia Lumia 920 (forthcoming)

Best midrange phones: Motorola Droid Razr M (Verizon), Samsung Galaxy Nexus (Sprint, Verizon), Pantech Burst (AT&T), HTC One S (T-Mobile)

Best basic phones: Samsung Gusto 2 (Verizon), Kyocera DuraXT (Sprint), Pantech Breeze III (AT&T), Samsung T159 (T-Mobile)

Design: Blend in or stand out?

A phone is such a deeply personal product, you might find yourself strongly drawn to one style or another. If you prefer a low-profile phone, good news. Most are black or dark-gray shingles, though white has become a popular color choice. Others come in edgier colors like red, cyan, and yellow, or with distinct shapes, edges, and backings.

Nokia Lumia 920

Whether you love it or hate it, the Nokia Lumia 920 design makes a statement.

(Credit: Nokia)

The Motorola Droid Razr line rocks a futuristic Kevlar fiber rear coating and has some interesting angles. HTC's Evo 4G LTE is handsomely made from anodized aluminum, sports flashy red and silver highlights, and boasts its own spring-loaded kickstand. The ultramodern-looking Nokia Lumia 920 also flaunts numerous and wild colors, as does the Sony Xperia P.

We still love the elegant, industrial designs of Apple's iPhone series, as well as the Samsung Galaxy S3's thin, molded-from-plastic, smooth, and attractive curves, which are sure to become ubiquitous (and therefore stand out a little less.)

Favorite stylish phones: HTC Evo 4G LTE (Sprint), Nokia Lumia 920 (forthcoming), Motorola Droid Razr M (Verizon), Sony Xperia P (unlocked)

Do you like a large, medium, or small screen?

A phone's single most important physical element is its screen size. You'll find the largest screens within the Android camp, the most massive being the tabletlike Samsung Galaxy Note 2 (forthcoming), which features a whopping 5.5-inch display. Its cousin, the Samsung Galaxy Note (T-Mobile, AT&T), is slightly smaller at 4.3 inches.

The Samsung Galaxy S3, HTC One X, and Motorola Droid Razr HD also sit at the top of the portable screen world with high-resolution displays of 4.7 inches or greater. As you can imagine, viewing everything from Web pages and photos to movies on these monsters is an awesome experience.

Samsung Galaxy Note 2: Samsung's next-generation phablet

The Samsung Galaxy Note 2 suggests a tablet with its mammoth 5.5-inch screen.

(Credit: Stephen Shankland/CNET)

Still, others prefer a smaller device that's more pocketable, and there are plenty of those to choose from. There's the medium-size Motorola Droid Razr M with an edge-to-edge display that, despite its slim, compact chassis, features a vibrant 4.3-inch screen.

For those with small hands or seriously tight pockets, the 3.7-inch HTC One V is a solid choice. Not only does it sport an elegant aluminum unibody chassis, it runs Android 4.0 and has a fully featured camera. Another superb pint-size option is the iPhone 4S, which, thanks to the iPhone 5's arrival, has dropped markedly in price.

Best "small" (under 4 inches) phones: iPhone 4S (AT&T, Sprint, Verizon, Cricket, Virgin Mobile), HTC One V (U.S. Cellular, Virgin Mobile)

Best "medium" (4-4.5 inches) phones: Motorola Droid Razr M (Verizon), Apple iPhone 5 (forthcoming), Pantech Burst (AT&T)

Best "large" (4.7-5.5 inches) phones: Samsung Galaxy S3 (Verizon, Sprint, AT&T, T-Mobile, U.S. Cellular), Motorola Droid Razr HD (Verizon; forthcoming), HTC One X (AT&T), HTC Evo 4G LTE (Sprint), Motorola Droid Razr Maxx HD (Verizon; forthcoming), Samsung Galaxy Note 2 (forthcoming)

How often will you use the camera?

If you're like us, your smartphone camera has become your primary shooter for casual, day-to-day moments. It's also a chief selling point for any phone.

Nokia, Samsung, Apple, and HTC are our go-to manufacturers for smartphone cameras, not quite in that order. Nokia's 808 PureView pretty much wows with its 41-megapixel sensor and some clever "cropping" techniques. We're hoping that the Lumia 920's 8.7-megapixel camera, which uses PureView processing algorithms (but a different lens), will also impress, but we can't even guess at its eventual photo quality.

Samsung's 8-megapixel cameras also take some consistently great shots, even in automatic mode. The Galaxy Note series and Galaxy S II and S3 phones seem to share the same camera characteristics, and we're not talking about the fancy sharing software, just photos in the raw.

Nokia 808 PureView

The Nokia 808 PureView's 41-megapixel camera is large and in charge.

(Credit: Josh Miller/CNET)

The iPhone 4S' camera is also at the top of the class, especially in low-light conditions, and the camera's strength is its ability to automatically adjust to a number of situations, from low-light to macro, without you having to futz with the settings. The iPhone 5 promises to improve it all, and adds a panoramic mode with 28-megapixel resolution.

HTC's camera takes photos with alarming speed, and while the picture quality is good, it isn't the best. However, HTC's track record is far better than Motorola's, which produces 8-megapixel cameras that can't quite get shots as sharp or as colorful as its competitors'.

Best camera phones today: Nokia 808 PureView (unlocked), Apple iPhone 4S (AT&T, Sprint, Verizon), Samsung Galaxy S3 (multiple carriers), HTC One X (AT&T)/HTC One S (T-Mobile)/HTC Evo 4G LTE (Sprint)

How powerful a phone do you want?

The mobile phone arms race is as hot as ever and, much as with desktop computers of old, manufacturers constantly vie for performance bragging rights. Similarly, elite smartphone shoppers pore over spec sheets and feature lists in a quest for the ultimate handset.

Apple A6 processor, Samsung Exynos 4, Qualcomm Snapdragon processor

Processors: Apple A6, Samsung Exynos 4, Qualcomm Snapdragon S4

(Credit: Screenshot by CNET)

Apple has introduced its A6 processor, of which little is known other than the promise that it's two times faster than the A5 chipset in the iPhone 4S. The top Android and Windows Phone dogs will use Qualcomm's dual-core Snapdragon S4 processors.

Manufacturers are working on getting LTE-ready quad-core chips into U.S. smartphones, and if the rumors are true, the first could belong to the Samsung Galaxy Note 2, which could comes with Samsung's own quad-core Exynos processor.

Honestly, though, a phone's clock speed is a relative value. A slower CPU can make efficient software fly while the opposite is true of a handset weighed down with useless apps.

For example, the Samsung Galaxy Nexus running pure Android 4.1 Jelly Bean is one of the swiftest-handling phones we've ever used, the iPhone 4S has been buttery-smooth, and the single-core Nokia Lumia 900 was plenty nimble.

Smartphone speed demons: Samsung Galaxy S3 (Verizon, Sprint, AT&T, T-Mobile), Motorola Droid Razr HD (Verizon), HTC One X (AT&T), HTC Evo 4G LTE (Sprint), Samsung Galaxy Note 2 (forthcoming)

Will you use your phone for calls?

These days, calls are often the last thing on a phone owner's mind, but if you care about talking in addition to your texts, games, and e-mails, you have a bit of a chore ahead.

Unfortunately, call quality is the hardest attribute to consistently pin down, since it vacillates so widely based on network strength in your location, your building, and even the time of day. What's good for us at the CNET offices in San Francisco or New York could be terrible in your neighborhood.

As a result, we can't in good conscience recommend specific handsets for their call quality.

Our best advice is to make a test call from a retail location (even if you're buying online) to check the call quality, and to ask your neighbors for an assessment. Some people still write us saying they can't get reception in their signal-blocking homes, but they can get it on the street.

How critical is long battery life?

Even the most high-octane superphone becomes a fancy paperweight when it runs out of juice. Compounding the problem are the swelling screen sizes and multiplying processing cores cropping up in modern CPU chips. Then there are 4G LTE radios that suck down data at lightning speed, but if abused, will soak up electricity like a gaggle of thirsty vampires.

Motorola Droid Razr Maxx HD

Motorola's Droid Razr Maxx HD tops the charts with a 3,300mAh battery -- wow.

(Credit: Motorola)

That said, a few handsets manage to sagely balance their energy consumption with swift performance. Other devices are also equipped with large-capacity batteries of over 2,000mAh or more, providing a deep reservoir to draw from.

Here's a list of phones we've tested personally that have demonstrated outstanding longevity or that likely will based on their components. Read more about the future of smartphone battery life here.

Phones with superior battery life: Motorola Droid Razr Maxx (Verizon), Motorola Droid Razr Maxx HD (Verizon, forthcoming), HTC Evo 4G LTE (Sprint), Samsung Galaxy S3 (Sprint), Motorola Photon Q 4G LTE (Sprint)