If you're an iPhone fan, you're going to really like the iPhone 4S.
If you've got an older iPhone or are considering buying your first, the 4S is a great device to get. If you've got an iPhone 4 or if you're an Android fan, though, it's not a must-have.
The headline feature of the iPhone 4S is its Siri voice control system. With Siri, users can do things like get directions, call and text friends, get restaurant recommendations, set countdown timers and find out metric-to-English conversions all by just talking to the device.
Users activate Siri by pressing and holding the iPhone's home button. After that, you use Siri by just talking to it naturally. You don't have to use any special commands; instead it is able to glean what you want from what you say. So, you can ask Siri, "How do I get to the California Academy of Sciences?" and it will give you directions to the museum in San Francisco from where you are.
The Siri technology is neat. I used it to look up directions, to find out how many milligrams are in a pound and to find nearby sushi restaurants. In many cases, it worked without a hitch.
But not always. When I tried to use it to call my wife, whose name is Tara (pronounced TAR-uh), it kept hearing "tart." While I was amused, my wife wasn't.
It also had a difficult time understanding me when the iPhone 4S was connected by Bluetooth to the hands-free system in my Prius. While driving, I tried to get it to give me directions to my house. But it couldn't figure out my street name no matter how many times or how slowly I repeated it. I ended up turning off Bluetooth and holding the phone in my hands so I could use its microphone rather than the one in my car. That finally worked, but it didn't give me a lot of confidence about using Siri legally while on the go.
The Siri feature has other shortcomings. Right now, it only understands three languages: English, French and German. Given the number of Spanish speakers in the United States alone, it seems a big oversight that Siri doesn't understand that language. Apple says that Siri is officially a beta product, and that it plans to add other languages in the future.
Also, Siri only works with a select number of applications, mostly those that come pre-installed on the iPhone. So when you ask for directions, it pulls up the iPhone 4S' native Maps program; you can't use it to get point-to-point directions on a GPS application that you may have installed, such as AT&T Navigator.
Siri is also subject to the limitations of those native applications. The iPhone's built-in countdown timer will only time things in hours and minutes, not by seconds. So you can't ask Siri to set a timer for, say, four-and-a-half minutes.
One other cool aspect of Siri is that it allows you to enter text by speaking it, rather than by typing on the iPhone's virtual keyboard. So, using Siri, you can dictate an email or a text message. The voice recognition was reasonably accurate, although I did have to go back from time to time to correct certain mistakes, but not any more than I tend to make with the virtual keyboard.
You can use the dictation part of Siri not only in native applications such as email, but also in third-party applications, such as Twitter or Facebook. When the virtual keyboard comes on the screen, one of the buttons has a microphone symbol on it. Press it, and you can start to dictate.
I found myself using this feature a lot and wishing it was available in even more places. For some reason, Apple doesn't let you use the dictation feature to enter a Web address or to input an email address when logging into applications such as Facebook. Instead, in those cases, you have to go back to using the virtual keyboard.
Besides Siri, the other big upgrade on the iPhone 4S is its camera. The new rear-facing camera sports 8 megapixels, rather than the 5 megapixels on the iPhone 4. That allows it to take bigger pictures, finer-grained still pictures, and videos in 1080p resolution, rather than 720p. You may or may not notice the difference. I didn't really in my quick tests.
What I did notice was that the camera is much, much faster than before - and much faster than other smartphone cameras I've used in the past. As long as you have the flash off, you can take photos in rapid succession, almost as fast as you might with a standard point-and-shoot camera.
I loved how quick the camera was. I take the bulk of my pictures these days with a camera phone, just because it tends to be the device I have on hand. But because their camera tend to be slow, my pictures frequently and frustratingly turn out blurry or out of focus.
Explore further: Gift Guide: Strong photo, video gear options
More information: Troy Wolverton is a technology columnist for the San Jose Mercury News.