I had my 3GS swapped out at the genius bar this past Sunday. There was a hairline crack on the back near the charging port. I am pretty sure it is a refurb. The battery seems to be draining quicker than my old device. Pretty much the same usage, maybe a tad more than usual. I charge it overnight and pull it off the charger about 7:30am. Moderate usage all day, usually hit 20% around 6:00-7:00pm. Now hitting it around 4:00-5:00pm range. Should I be concerned? Does the battery need to be broken in?