orcishgamer: I've never heard any such thing from anyone but irrational fanboys who'd literally never run an ATI product in their life. Even back in the 9800 Pro days I ran WOW like a champ raiding and we always were waiting on nVidia folks to "just a sec, reboot". My ex was running a 9700 Pro and likewise had no issues. It's anecdotal, but when I couple in the fact that I actually have tried to run 2 different nVidia cards over the past few years and had nothing but problems with their higher end cards, problems that I never had with ATI, I'm done with nVidia. nVidia also has a habit of removing support (read as hacks to make it actually work) for older games, this is a big no-no in my book.
abolat: Well I ran ATI cards all my life too but the lower to mid range ones as this was all I could afford. I was thinking of building a new system now that I have some money saved up and the graphics card is all that is missing. I was going to go with the 6970 but when I asked on some hardware forums the responses I got were along the lines of "a gtx 570 can easily beat a 6970 and plus it has physx which is amazing and makes all the difference in the world. you've waited this long and now have the chance to get a good system, so get the best man. wait for the 6xx series to come out and get a 580; the price will go down then and a 580 beats a 6970 anyday"
I have a pair of 6870s in my rig I just built. The 6970 is a nice card and probably a net win if you consider power issues over Crossfire with a pair like mine. I'm not sure what games these guys are playing that cause physx to "make all the difference in the world", my bullshit detector goes off when I hear that kind of thing.
All I can say is even with my cards there's nothing, and I mean nothing, that's even giving them a reasonable workout. If you've been happy with ATI quality in the past then there's really no reason to switch, there's no way you'll notice any real difference between a gtx 570 and a 6970 while playing games. By the time the system is aging you'll need to upgrade either one to eek out the last few years from the rest of the hardware so I see it as a non-issue, aka mental masturbation by people who like to read Tom's Hardware a little too much.
In the end, you can get bum hardware from any company, I just don't trust nVidia at all. If you've been unhappy with ATI you might give nVidia a shot to try the competition, but if you've been happy, why fix what isn't broken? It's not like the 6970 isn't going to run every game on max for at least the next 2 years and on high for a year or two past that.
In the end I suggest you build the machine that isn't going to disappoint you whenever you look at it. If you spend 1200 USD on something that irritates you whenever you boot it up you'd have been better to not spend anything at all or to have spent the extra cash to build what you want (provided your children do not starve so you can do so). That's my little personal philosophy about all of this:)