The iPhone 4S may not be everything for which the Apple fan base had hoped. It doesn't have an LTE or WiMAX radio, the form factor remains the same as the iPhone 4 and the device lacks an NFC chip.

Those things aside, the iPhone 4S, which presumably lands as the 3GS did between the 3 and the next whole number in the iPhone sequence (in this case the iPhone 5), is no slouch by any means, but it may not be for everyone. In typical Apple fashion, the iPhone 4S manages to play a quick game of catch-up with newer Android models while also giving users some new features that are simply not available anywhere else.

Under the Hood
I'm going to guess that lack of a new form factor was perhaps the No. 1 reason for the initial letdown after the iPhone 4S unveiling. Consumers, and especially those aware of Apple's revolutionary design aesthetics, often expect a visual punch as much as they expect a technical one. Granted, some understand that a dual-core processor means more speed and that an 8-megapixel camera means better quality photos, but in the end, they want something that just looks new and fresh.

Hero iPhone 4SWhile the iPhone 4S may not look much different on the outside, it is a completely new phone on the inside. So while consumers may not see an aesthetic difference, they'll certainly notice the results of a major under-the-hood revamp.

Those amongst the 4 million who purchased the device in the first three days will notice considerably faster performance given the dual-core A5 800 MHz processor. Call quality is also better due to intelligent switching between two antennas. AT&T users will notice faster speeds because of support for HSPA+ connectivity. And travelers will be able to switch between GSM or CDMA networks as they roam. Perhaps dry improvements, but definitely an upgrade.

On the connectivity side of things, I've been able to receive and maintain calls in my office for the first time and download speeds have hung right around 3-6 Mbps, which isn't outstanding but definitely an improvement over AT&T's traditional 3G data speeds.

The new 8-megapixel camera is perhaps the sexiest of the internal upgrades. After seeing pictures taken with other 8-megapixel mobile cameras, I can confidently say that this is one of the best on the market. But users might find this upgrade most noticeable in the videos they take, as the iPhone 4S now supports 1080p video capture. I took some home videos and played them back through AirPlay on my flat panel, and the results were truly stunning.

While these upgrades are just that – upgrades – and perhaps not reason enough for many to sign an additional two-year contract, the true reason to land an iPhone 4S is Siri, the new virtual assistant. A better camera? Fine. Faster, more reliable connectivity? Fine. Faster processor? Good. Revolutionary experience? Siri.

May I Help You?
When Apple acquired Siri in April of last year, it seemed an off-hand pick up by a company with loads of cash to spare. The virtual assistant was immediately yanked from the App Store and little was heard from the company until the unveiling of the iPhone 4S. Well, we're hearing from Siri now, loud and clear. And while Apple's new assistant has been mocked, panned, lauded, ignored and praised, I'm going out on a limb and suggesting that this has done for speech what the touchscreen did for our fingers.

Everyone reading this review has probably seen at least one video of someone demonstrating Siri. You get the picture: talk to your phone, and Siri tries to accommodate your request. After playing with and abandoning apps like Nuance's Dragon dictation, which is impressive in its own right, I had no idea why anyone would get excited about yet another speech recognition app for a smartphone. To put it bluntly, I had kind of given up on the idea of speech as the next killer app.

Then I met Siri. It appears that deep integration at the hands of a skilled player like Apple is what it took to make speech recognition a game-changer. If one-click used to be the golden standard for UI developers, a single spoken sentence is perhaps the new goal.

Perhaps the greatest misconception in these early days since the iPhone 4S was released is that iPhone users everywhere are going to be annoying people worldwide by incessantly speaking commands to Siri… in public. While some users might do just that, the bulk of users are going to task Siri with creating texts and emails while driving via Bluetooth device. They'll also be setting reminders and alarms and finding the nearest dry cleaner but not while they're standing on the subway, rather from the comfort of their car, hotel or living room.

What's perhaps most surprising is how well Siri detects and acts on natural speech commands. The key here is "natural." You don't have to use a specified set of commands so Siri will understand you. I've asked Siri to remind me to pick up the kids after I leave the house, and it does just that using a GPS-based proximity alert, which is linked to my contact information where I have my home address entered. I've asked Siri in three or four different ways to wake me up at 6:30 a.m. and it does just that. To be fair, and in the interest of entertaining those who mock my new virtual assistant, I've also asked Siri for the meaning of life, and it told me "42."

Misunderstandings and hyperbole aside, Siri is just the tip of the iceberg. Siri will get better, smarter and more integrated in the future. I was disappointed that I wasn't able to open an app by saying the name of that app, and yes, occasionally this virtual assistant's miscues when dictating a text are on par with the failings of autocorrect. However, not only is Siri a brilliant implementation of a technology that has long been available but not fully capitalized upon, it will also drive the usage of SMS for years to come. Folks with poor eyesight or fat thumbs will welcome this new feature with open arms.

I'm maybe a little surprised to find that the camera, world phone connectivity, a new processor and Siri are really the only reasons to upgrade to the iPhone 4S. I originally upgraded for the better camera, but after further review, I have to say that it is Siri that has most impressed me. 

iOS 5, iCloud
The iCloud and iOS 5 are available to anyone with an iPhone 3GS or higher, so they're not specific to the iPhone 4S. However, I still feel like they're worth a few comments. If you stand up on the iCloud and look down at the iMac, AppleTV, iPhone, iPod, iPad and iTunes, what you begin to see is perhaps the most sophisticated ecosystem of devices and software ever designed for the consumer. The content is there, the billing is there, the hardware is impeccably designed and the UI is nearly flawless. The devices talk to one another seamlessly, and Apple TV wirelessly brings HD mirroring of videos, music, photos and apps directly to the flat panel in your living room. Not only is this ecosystem state-of-the-art, the possibilities inherent are endless.

While there are glimmerings of genius cropping up every day in the Android ecosystem, from apps to new hardware (I'm particularly interested in the upcoming announcement from Google and Samsung), Apple boils it down into one cohesive package. To achieve what Apple does with its software and hardware, an Android user would have to employ a variety of solutions, with no guarantee that everything will play nice together. Apple's plug-and-play vision simply does not compromise on the user experience side of things, which in the end has both delighted and at times infuriated users of all walks.

To summarize, the iPhone 4S is admittedly an upgrade and a catch-up, but its core “one more thing,” Siri, just feels like a game changer. Those consumers not necessarily interested in Siri, increased speed or a better camera might be content waiting for the iPhone 5. For those who do decide to wait, Apple has outdone itself with the new iOS 5 and iCloud product offerings, which keep both the 3GS and iPhone 4 neatly within the fold of this continually evolving ecosystem.