evga...I've owned 3 eVGA cards, 6600GT, 6800GT AGP, and a 6800GT PCI-E, great cards and overclocked nicely as well.
They use high grade parts like japanese capacitors and such for their cards. Very low failure rate compared to XFX.
That difference of 10MHz in memory speeds can easily be made up from overclocking. Get an aftermarket cooler and you'll be to overclock the crap out of it.