Interesting detail I noticed: AMD cards seem to be better at high resolutions, nVidia rules suppreme at low resolutions.
This game has made me consider replacing my 3 year old 3850 (which runs perfectly at low specs) with a more modern 6850. If I want to see Ultra specs (without Ubersampling, obviously, but I don't see any meaningful difference in their comparison screenshot anyway), the 6850 looks like a very good buy.
It'd be the first time in my life a game has made me buy a new video card, but I'm not sure it's really worth it. Low specs still looks awesome. Does Ultra really add that much more?