hi i am going to buy a new Iphone 4S from a local Apple retail very soon. I am completely newbie to it. but I am a serious buyer I don't want to get something unhappy I have been research on web and find out something I need to check about when I first get a brand new Iphone 4S from the staff, I would llike to know if I've missed anything about that. check IMEI check the model part check dead pixel check whether any yellow line / splotches check button responsivness check camera by snapping a shot and using flash check sound quality by making a test call cosmetic - check whether any scratches or rough edge. is there anything else? anything I've missed? Thanks!