personal opinion often leads to fanboy wars. alot of the people on this site will give you REAL advice based on facts depending on your needs as a gamer; the info on your setup and future plans for gaming is very important in choosing the correct gpu for your situation. What you are running is very important to what is recommended, so stop trying to be vague and to the point if you want real help. Thats like comparing a gala apple to a fuji apple, some people like one or the other.
im pretty sure that amd's typically are better at high resolution so that could push you that way and i would do some research as to which one could overclock better cause that could push one over the other. you might look into crossfired 6950's and unlock the extra shaders and they will both combine to overclock better then the 6990 and will have the same performance or even better for less unless this is somewhat of an ego build in which case if i had the money id prolly want a 590 or 6990 just to say i had it.
Jesus H Christ. I want to know and i ask to. If you have a problem with that then you know what to do. I'm not getting the 6990. I am getting the gtx 590 instead which after all (cuda processors,physX,benchmarks,etc..) is better than 6990.