I was getting pretty bad battery life from my sprint 16gb, would start the day at 8 am with 100% and with very light email and browsing on 3G I would be at 40 or 45% by around noon, this morning I got a brand new AT&T 4s (sprint data speeds sucked) and my battery is way better, I have been using HEAVY since 10 am on 3G and I am at 72% right now, so if maybe there is a bad batch of batteries? I don't know, but this new phone is like night and day as far as battery usage.