nVIDIA makes total junk. They always have. Sure, it's fast performing junk (but they're also known to cheat on benchmarks by lowering rendering quality when they detect a benchmark)
ATI has always been more reliable, more stable, better rendering quality, and better supported - if not as fast.
Look at what nVIDIA did to 3dfx customers when they bought 3dfx - they immediately ceased releasing drivers, not even releasing an XP driver. Just dropped all support immediately, even for the most recently released 3dfx cards.
nVIDIA has ALWAYS been a lousy company that has an excellent price to speed ratio. You get what you pay for and I'm glad to see Apple turning away.
Oh, P.S. yes, I own a new 13" MacBook Pro and am TICKED about the SATA issues that the *nVIDIA CHIPSET* is having. Oh, and yes, I had a very recent (a few months before the buyout) 3dfx card years ago and was TICKED that it wasn't supported in XP because nVIDIA immediately dropped 3dfx driver support. nVIDIA has shown me time and again they are worthless. Oh, ask anyone who bought their 3D shutterglasses setup they sold then quit supporting. Or... Or...
Honestly, I was tempted not to buy the new Mac just cause of the nVIDIA chipset but figured all companies can make good for the right price, and Apple must be getting the best nVIDIA has. I'm learning how untrue that is with the SATA issues...