I've been using my iPhone since I pick it up on Friday morning. I'm not a heavy user, but compared to Galaxy Note 2 that I used, I'm happy with the battery performance. It definitely last more than a day for my usage pattern, and best of all, when I turned it on this morning, the battery percentage didn't go down much at all. With Note 2 which has a much bigger battery, it drains battery even in idle not even receiving any emails. I was one of those who were disappointed by the battery size of iPhone 6, but I am fine with the performance so far. Yeah, I thought about what if it has 2500mah battery, then it'll last full days for me, which isn't the case with my Note 2.