I've only had my GS since October 20, so I have til November 20, but I think I am going to stick with the GS2.
For email, messaging, and web browsing, I just don't really think I will benefit that much from LTE. But it's a near certainty that my battery will detriment from LTE.
I'm also not convinced that the screen's resolution is high enough for 4.5". I think 4.3" at this resolution is pretty nice though (although would prefer higher).
In short, longer battery life is more important to me than getting 15 mbps, so I will likely be sticking with the GS2.
Oh, and yes, I do live in an LTE area. (DC, which is supposed to be getting turned on the same day the skyrocket comes out).