Ive been playing with computers since 1984 with the Kaypro 10. Ive probably owned a shit load more cards then that guy and I can say Ive only ever had problems with a single ATI card, a 4850 512MB. Ive also had a problem with a Nvidia card...an 8800GTS 640MB. The Nvidia card blew up, the ATI card just crashes sometimes. Doesnt that mean ATI is better?
Nope.
Fact is both companies have had their share of problems...and both companies have shipped out a bad card or two. When talking about high end features like multi monitor and 3D support neither one is perfect and both are relatively new. Its gonna take time before every new game works perfectly with either setup. Older games will most likely never work right, just the way the cookie crumbles. Doesnt mean those technologies arent worth investing in...theres already several good examples of their potential. Nobody questions a 700$ TV purchase, theres no reason to be discouraging the people who would get far more enjoyment out of a 700$ PC monitor setup.