S3 battery life is plenty for me. I did over 2 hours screen on today, with ~60 minutes of streaming HD Youtube and MLB.tv, around 30 minutes in Google Nav, a little bit of Angry Birds and web browsing, speed tests, streamed Pandora for ~1.5 hours, all on LTE during the workday. Also was disconnected from charger for over 13 hours. My battery is now at 40%. Seems pretty legit to me, my thunderbolt would have been dead by that time even with custom rom/kernel.
If you spend 3+ hours a day with your phone screen on, maybe consider getting a tablet?
Also to the size haters about fitting in pockets--seriously? I hate putting anything in my pockets, but the S3 is so slim, even with a case, it slides in and out of my front or back regular jean pockets with ease, and I can barely notice it. Maybe lay off on the skinny jeans?