My 8600m GT may have been broken too I guess.
Anyway they have Phys-X, better OpenGL drivers, more OS support, lower power usage, (alternative methods for anti-aliasing and lighting too I believe but I don't know what AMD have there) and G-sync. Better proprietary drivers. Still not at least as good open ones is a fair thing to say?
AMD have Mantle and Adaptive-Sync and
Mantle I suppose will be pretty irrelevant vs new DirectX 12 and OpenGL.
Just as G-sync should be allowed to become irrelevant if Adaptive-Sync let you make the same thing in a standard way.
Just suck that Nvidia is big and common enough that they may get away with not supporting it and do their own thing