People wanted an iPhone 5. A top-secret new phone to deliver previously unknown pleasures, and to cast the 16-month-old iPhone 4 into the rubbish heap of planned obsolescence. But the news on October 4, coming just a day before Steve Jobs's death, was a reminder that not every Apple announcement blows off the roof. So here's the 4S--faster, Sprint-ier, with a better camera to see the world, and Siri, the voice-recognition assistant to better listen to it. And the proverbial question: is it worth an upgrade?

Like the iPad 2, the iPhone took a class-leader and subtly but smartly improved it, without breaking any moulds. In this case, there were literally no moulds broken: the iPhone 4S, save for a few variations in its aluminum antenna to improve the iPhone 4 "death grip," is physically identical externally.
But unlike the iPad, which is the undisputed tablet leader, the iPhone has some competition in the very-nice-smartphone market, most of them running Android and, more recently, a few of them running Windows Phone. So while the decision becomes a bit more complex, it's tough to find a smartphone package as powerful, elegant and self-contained as an iPhone 4S. But do not despair, iPhone 4 owners: much of the new magic is bottled in the iOS 5 update.
WHAT'S NEW
As usual, the iPhone 4S's processor gets a bump from the iPhone 4's A4 to what Apple calls the A5--the same processor family found in the iPad 2. The camera, now at eight megapixels up from five, shoots 1080p video and has an improved lens and sensor. And then there's Siri, a voice-recognition software assistant that Apple says can only run with the 4S's stronger processor.
WHAT'S GOOD
Everything new is good. Compared with running a fresh install of iOS 5 on an iPhone 4, the A5 processor boosts performance across the whole operating system. It doesn't blow the A4 chip out of the water, but in a touch interface, even small gains in responsiveness as you swipe and tap from screen to screen make a huge difference in your perception of speed.
I can also verify the camera improvements are legit. Noise levels in low light are still not as good as my S90 point and shoot, of course, but they're significantly better than the iPhone 4, which was already pretty adept in low light. In many more well-lit situations, image quality is actually getting pretty close to a high-quality point and shoot when you're looking at the photos on-screen. Colors are natural, tap-to-focus works, and with iOS 5's lock-screen camera button and the option to use one of the volume buttons for shutter release, the iPhone 4S is a pretty solid camera that you always have with you. That's great. (Our friends at Popular Photography will be publishing a more technical test very soon).
And then there's Siri. Early reviews were swept head over heels with her, but she and I have had a bumpier start. Siri misunderstands what I'm saying fairly often--I don't know if it's because I still have a hard time speaking naturally to my phone, because it's what I think she wants? Maybe it's because I've never in my life had a personal assistant, and I'm just not quite comfortable with the social norms of such a luxury, and she can hear that in my voice. Or maybe we just weren't meant to be?
When we do click, the effect is undeniably pretty magical (which is why this is filed under "What's Good"). I've especially enjoyed talking to Siri through the headset microphone while walking--squeeze the button, ask "are there any Radio Shacks nearby" (I needed a camera battery!), and if all is understood, the results are ready in your pocket when you pause at the next crosswalk. That's pretty nice. I can imagine the effect is even more satisfying for drivers.