I am really looking at geeting the S3, Currently I am using the boring Iphone 4s had all the EVO's but took too long to charge from 0-100% (4 Hours on the LTE) The 4s takes half the time and the battery life is better.
Speaking of the Battery, lIfe is not the only issue but also battery charge time. If your phone is always charging then draining fast whats the use.
When I went to bed yesterday, it was at like 58% and I set it to charging. I decided 10 minutes later that I couldn't sleep so I took it out from charging and it was at 67%. Not exactly the best trial but hopefully that helps somewhat :P
I also using Jelly Bean and stock charger.
From 0 to 100% need more than 4 hours
After upgraded to Jelly Bean feel that the battery takes longer time to charge compared to ICS only need around 3 hours.