I picked up the XFX 6600GT the second day Newegg had it and the deciding factor was the dual-dvi. Sure I only have a single monitor now, AND it's a crt, but I don't want to limit my future options. I should probably try the other port to check it out. I can say I have e-mailed XFX twice about nVidia driver bugs, and they've immediately responded both times. If I could send a message to nVidia directly I would, but don't see anywhere that I can. Great card, and the few driver bugs are very minor, nothing to get upset about, especially considering I did buy the card the second day after it was released. They're probably fixed in the 71.20 or whatever drivers, I've got the 67.03's.
So I don't know how XFX stands on rma's, but as for responding to tech questions they do a quicker & better job than most other companies I've tried to contact.