A bit of a back story. I was not planning to upgrade from the 4 to the 4S since the update was underwhelming, but I discovered that I had an upgrade which was not being used so I decided to bite. Thankfully, I will have another upgrade this coming summer, before the release of the 5. So, is it worth it if you have an iPhone 4? Read on... The first thing I do is load up Safari on both the 4 and the 4S (after restoring the 4 to stock iOS 5). The 4S opens it up SLIGHTLY faster, bringing out the bookmarks bar a millisecond sooner. Next, I load up The New York Times on both. Once again, the 4S loads it a tiny bit faster. Both the 4 and the 4S start showing text at the same time, but the 4S finishes the loading the whole page sooner. Again, it's barely any faster. Pinch to zoom is the same. Less checker boarding, but you still occasionally see it. All in all, it's pretty much the same deal. Applications open a hair faster on the 4S, but again, it is a marginal improvement. The camera opens a second quicker, but it still isn't instant-on material. Photo's look nice, but I was satisfied with the 5 megapixel shooter on the 4. Siri. It sounds like a gimmick. It looks like a gimmick. Is it a gimmick? Short answer: Yes. I played around with it, asking it to text a friend, get me the weather, and so on. It's a cute toy, but manually doing the task is still much faster. The only use I see for Siri is using it while driving. It works maybe 20% of the time for harder questions (like what is the derivative of sinx to the 37th power), relying on Wolfram Alpha for answer. I can see it being more useful if it worked faster, and maybe with time it will evolve, but as of now it's just a marketing ploy. Is it worth the upgrade? If you are like me and have an extra upgrade and $200 lying around, why not? I own a Droid Bionic (4G LTE) as well, and I can recommend the iPhone 4S over it any day. 4G gives insane speeds, but it eats the battery life faster than I can charge the phone. Also, Android, especially the browser performance, is not up to par with iOS (but it is slowly and steadily climbing up the ladder). If you have a 4 and were thinking of upgrading for full price, don't bother. It's barely any faster and it looks identical to the 4. Siri is not nearly as handy as it is portrayed to be, nor does it work most of the time. Just my $0.02, take it for what it is.