What advantages? From what I hear Vista isn't any better for games than XP. Check out this Gamespot article, from those comparison images I see a at best minimal improvement in eye candy and a significant reduction in frames per second.
Exactly.
Oh ... and I added Crysis to the title.
Here is a link to some good comparison shots ... DX10 v DX9 ... http://uk.gamespot.com/features/6182140/index.html?tag=topslot;title;2&om_act=convert&om_clk=topslot
also ... maybe a DX10 effect we haven't seen yet ... http://www.rage3d.com/board/showpost.php?p=1335211114&postcount=793