I bought three 4S's from Sprint and at least one* of them has completely unusable battery life (never sleeps, goes from 100% to 0% in ~6 hours even if it's never touched, gets overly hot all the time, etc) so I'm going to take it in to an Apple store for an exchange (as soon as I can - nearest store is about an hour away). I would like to upgrade it from a 16 to a 32gb as well, if possible. Does anyone know what the rules are for that? As it's within the 30-day iPhone "satisfaction guarantee" period so seems like they may be able to help. *One other has intermittent battery issues as well. Some days gets 5.5-6.5 hours of use and 16-20 hours between charges, other about half that. It has also shut down randomly a couple times and when it came back on wifi didn't work at all (just said "no wifi" and the toggle wasn't available to change), though a reboot fixed that. Going to talk with them about it, but think I would prefer a new device. The third is perfect though!