So, this is wierd. These two screenshots were taken with the exact same settings but the first is running with the DX10 exe and the second is with the DX9 exe. In both shots all settings are as high as they will go and the resolution is 1360x768. NV control panel settings appear to have no effect under DX9 or DX10 so I'm using the ingame AA setting which only has 3 levels and for both shots it's at level 3.
I started off playing the game in DX10 and performance for the first environment seemed just fine. Now that I've moved to the second location performance is pretty bad with the highest settings under DX10 at my resolution which is what promted me to give the DX9 exe a try. Performance under DX9 is significantly better but it doesn't surprise me when it looks that terrible.
Oh, and I know the DX10 image is windowed and the DX9 is not. I don't know why but for some reason in Vista DX10 and sometimes DX9 screen grabs with printscreen will come out as if the game is windowed even though it clearly is not windowed when you take the screenshot.
I'm running Vista x64 with the 169.25's. I should try some newer drivers to see if there's any change.
DX10 (1360x768, all settings max)
DX9 (1360x768, all settings max)