Nvidia at least have dual planes ability in their game cards as well the Quadros,with ATI you have to buy a Fire GL to get it.Dual planes gives you the ability to have many many objects in your veiwer window and be able to move them all around more easily within a 3D app,dont know if it would make any difference or not to gaming,am assuming not.
In my experience ATI card last longer and maintain high performance throughout their lifetime. nVidia's have broken down peristently in my experience, wearing out, and seriously degrading in performance over a relatively short period of time. Go ATI.