sapphire has a lot more warranty problems than others, but they generally sell more cards so that's a wash in my opinion. my big concern is not the failure rate of items but BS like a $15 rma fee or the rma nazi on the sapphire forums.
um, having said that, if my 4850 ever breaks I'll be sure to make nice with sapphire...wait, I can't since I oc'd it...oh well, hopefully evga will either be selling ati cards soon or nvidia will be making somewhat reliable cards during the next round anyway...