I've had 3.5 hrs of usage, mainly calls but also a day of emails and a few iMessages.  9+ hrs of standby and I'm at 68%.  I'd say that's pretty good, especially considering brightness is up above 1/2 way mark.  If I can pull down 6-8 full hours of use, I'm good.   I've yet since the day I picked it up to come dangerously low.  However I do have a battery backup plug if I'm in a remote area with no power available.