I've had the iPhone 3GS for a week now, so I thought I'd share my impressions as someone who upgraded from last year's iPhone 3G. There are dozens of excellent exhaustive reviews out there (see Engadget and Gizmodo's take, as well as that of the New York Times' David Pogue), so I'll just touch on the things that stand out the most for me.

• The "S" stands for speed. That's what Apple says, and it's definitely the most noticable improvement over the 3G. Yes, the 3GS is more of an "evolutionary" upgrade rather than a "revolutionary" one, but if you use your iPhone as heavily as I do, the miliseconds add up. When scrolling through and starting apps, loading web pages, and just tapping here and swiping there, the iPhone 3GS is simply snappier. The time it takes between launching Tweetie to seeing the first tweet is barely two seconds on the 3GS, versus nearly five on the 3G. And up until now, I figured the delay in loading a complex web page in Safari was caused by the 3G data network. With the 3GS, I now know that as much of half of that wait is attributable to the hardware simply sorting everything out.

• A much better camera. Even though I have a decent digital camera, I've all but stopped using it. My iPhone has become my main camera, simply because it's always with me, and because I can publish the photos from anywhere. And while the 2-megapixel camera of the 3G wasn't awful, it wasn't great, either. It had fixed focus, so you couldn't take a picture of anything closer than six or so inches away, and the color and low-light performance left much to be desired. By comparison, the camera in the new iPhone 3GS is spectacular. It's got a 3-megapixel sensor, which nets print-worthy shots. It has autofocus and macro capability, so you can take close-ups like this. And it makes intuitive use of the iPhone's touch screen: just tap where you want the camera to focus and adjust its white balance. As Andy Ihnatko says, "Awesome."

• Video. iPhone users have been clamoring for video recording since day one, and the iPhone 3GS finally delivers. Sure, you could hack your iPhone 3G, and the quality wasn't bad, but the hardware just wasn't built for it. The iPhone 3GS supports VGA (640x480) video at 30fps, which is pretty good for a phone. Even better, you can edit video right on the iPhone 3GS, snipping extra or awkward seconds off the beginning or end of a clip. Then, you can e-mail or upload your video right to YouTube or MobileMe. You might need to edit a bit, since there's a size limit to the videos you can publish directly from the iPhone 3GS (I'd guess about 10MB, or two minutes). And the iPhone 3GS applies compression to any video it sends out. But the good news is you can get the full-size, full-resolution video off the camera when you sync the iPhone 3GS with your computer. And the full video files, which work out to about 22MB a minute, look great. Here's an iPhone 3GS compressed video (which still looks good), versus the original file.

Unfortunately, though I was excited about Voice Command, I've not been able to get it to work very well. (No matter what I say, it dials my wife, which makes sense in a strange way.) Here's hoping future software releases improve its speech recognition. And the Compass? I only wish I traveled or got lost often enough for it to be useful. I may change my tune when we finally get Google Street View in Hawaii.

Some of the best improvements, of course, come with iPhone OS 3.0, which you can get for free on older iPhones and for $10 for the iPod Touch. One software feature that I didn't anticipate, but now find vital, is Spotlight search: the ability to search your entire phone, whether you're looking for an address or an application. I was most excited to get the long-awaited copy-and-paste, the long-awaited "Notes" sync, and stereo Bluetooth. "Find My iPhone" was enough to get me to upgrade to the MobileMe "Family Pack." ($149 is worth it for four iPhones.) There's also landscape keyboard implementation in more places (though I'm already used to the narrower standard keyboard), voice memos, and "shake to shuffle" (and "shake to undo"). Thanks to AT&T, we don't have MMS and Internet Tethering yet... but neither are priorities for me, anyway.

Any downsides to the iPhone 3GS? I have to say, my battery runs down noticably faster. The reason, though, is obvious: now I'm using Bluetooth, and now I'm using "Push" (which is needed for "Find My iPhone") and several apps with "Push Notifications." With the new battery meter, I can see how running more connections more frequently affects battery life in near real-time. I'll have to pick up a second FastMac iV for Comic-Con, as I'm sure I'll be taking even more photos (and video) than last year.

Ultimately, the iPhone 3GS was a worthwhile upgrade for me. My iPhone all but runs my life, be it via email, calendar, contacts, Twitter, IM, and a dozen other ways. It's my primary camera, and I adore the video capability. I was fortunate that I was eligible for the $199/$299 upgrade pricing, though. If you've got a iPhone 3G and you're not as reliant on it as I was, you can probably stick with it and simply enjoy the spoils of iPhone OS 3.0 for free.