just chiming in on this subject since it was at the top. I've had my phone for 4.5 days now, so far I have been extremely pleased with my battery life, especially when compared to my Captivate.
AT&T is my carrier and right now, Id say most of the time Im connected to wi-fi, but when Im out and about, a majority of the time that I look at it the phone is on 4G LTE.
The first full day I had the phone, I wanted to run it down completely so I could give it complete charge that night. I was still setting up the phone, so I was constantly on the market downloading and installing apps, moving things around, etc. By the time I got home that night, I still had 29% left on the battery. By the time I got into bed I still had 15%. I finally got to sleep at Midnight after spending the rest of the evening browsing the net and updating my bookmarks to kill the rest of the battery.
Since then, with normal use (at least for me) which consists of a decent amount of texts, I handful of 10 - 30 min phone calls, checking email, facebook, twitter and some other apps,
by 8pm I still have 45% or more battery life remaining.
Even when my Captivate was new, I don't recall having that much battery life at the end of the day. So far I have no complaints in the battery department with this phone. There are some other areas which I have a small beef with, but nothing to discourage me yet.