Well, I have some Aces High measurements.
Now as you know, there's no built-in, repeatable framerate benchmark in AH. As such, measurements are very subjective, and exact conditions cannot be duplicated.
So last night I went into the Late War Blue arena, changed to Rook (the country with the least citizens on) and went to a base under heavy attack, and joined the Cap.
The amount of activity, including GVs, Ack, lots of bombers, and lots of friendlies and enemy planes , made for a very busy environment.
My framerates in XP tended to be between 45 and 65 when there was "a lot of stuff" on the screen. Empty or lightly filled sky generally gets me 80+ fps.
My framerates in Vista tended to be between 20 and 50 when there was a similar amount of "a lot of stuff" on screen. Empty or lightly filled sky generally gets me 75+ FPS.
Video drivers were set to have the same AA and other features, and the Detail Level and Range sliders were *probably* identical. (Textures were 512 for both.) I say this becasue there really isn't a good way (that I know of) to transfer what must be identical visual detail settings from one AH installation to another, so I had to eyeball it. If anything, I think the Vista sliders were probably set to slightly more detail and range.
(Skuzzy: if you know how I can do this, please let me know, and I'll repeat this.)
Framerates notwithstanding, the overal smoothness was GOOD for both OSes. Though I was only up for 1/2 an hour, and i was using a cheap twisty stick instead of the full thrustmaster setup, I found the Vista gaming experience totally enjoyable. VOX and surround sound support was great. There weren't any stutters or jerkyness. Honestly, it seemed perfectly normal, except for the reduced framerate, and again, this may be related to tweaking AH some more.
As such, I am willing to state that, if you have a pretty fast system with a great video card (and any new computer that sells for $1200 should qualify as of January 2007), then AH should run perfectly fine in Vista.
In fact, I am surprised to report that most of the games I'm testing are working just fine in Vista. A little slower, but fine...
-Llama