I've had the battery for a little while now and have some observations:
The internal computer in the battery is not very accurate, last night after a day of heavy use it was around 30%. After sitting idle on the couch for a few hours it was 41%. Calibrating the battery has no effect.
Its hard to kill, there's no need to be turning your wi-fi and 3g data or anything the battery goes and goes and goes.
I actually like the thicker phone alot more, easier to grab. i just wish the cover had a rubbery surface