S!
Well, AMD had problems with original IL-2 that were FIXED! I know that for sure as I used both AMD and nVidia in IL-2, since beta as well. And I tested beta on TNT cards, Kryo cards etc. to get feedback to Oleg's team. Talk about a swap-o-rama and numb arse testing!
nVidia and AMD both make good hardware that run any game today. Even I could not use Water=4 straight with AMD there were ways to get around it, but for me FPS was more important than some a bit shinier water

AMD gave me a solid 60fps with VSync, that is all that mattered at the time. So did nVidia cards I owned(up to 580GTX). So better not say AMD was nothing but trouble with IL-2.
What annoys me is this nVidia lobbying "let us give you some money to game developing..in exchange we give code that gimps AMD and you have to add that TWAT logo spinning at start up"..Every freaking game nV is involved with has something extra installed that AMD can not use..look at Skyrim and some other titles. PhysX is just a gimmick, won't go into that. AMD is not any better in this regard either so "pot and kettle"
I pondered hard if I should go for 680GTX over my current 7970HD. I did not as it does not offer anything SIGNIFICANTLY better in IQ or performance in games I currently play. And those titles are not seen in the hardware reviews, go figure. In CoD for example AMD and nVidia are equally good performance wise..if nV offers me only very little increase in FPS the cost difference for that is too big IMO, even the card itself is a good one. So I settle with 7970HD for now..next time I will review need for a new card is when the 8xxxHD and 7xxGTX series come out next year. No need to slap ePeens around which one is better before that