I'm on my 3rd ATI card, my first was a complete pain in the arse, machine would reboot with no reason (had to but a new motherboard to get it working) and now likes to boot into Windows with nice blue lines across the screen on occasion, reboot, still there reboot again they're gone, maybe. This card is an ASUS A9800XT, a search on googe for A9800 +reboot reveales it's not just me.
Almost gave up on ATI but I later purchased a 9800Pro for my dad's machine, and later upgraded the 9800XT to a 1900XTX, both work, never given me any problems, they are both Sapphire...
I'm sure other people will have the opposite opinion, but I will never buy anything ASUS again and until Sapphire balls up they will be my first choice.
p.s. I have no opinion on Powercolor 🙁