I can't speak to the iPhone 4 vs iPhone 4S, As I had a 3GS. But holy crap is it a lot faster than the 3GS. And the 3GS wasn't slow, especially after the iOS5 update massively improved the 3GS. I am loving the 4S so far. The apps load much faster than my iPad, which is as close as I can get to the iPhone 4 speed. You click the icon, and the app is open. No wait at all.
Add in the fact that I'm consistently getting between 5-6Mbps down over HSPA+ and I love it so far.
Add in the fact that I'm consistently getting between 5-6Mbps down over HSPA+ and I love it so far.