Yeah, I generally find Vista's aero performance to be spotty. Low framerates and jerky animations. Why? Because Vista has my GPU clocked to 100/100 despite running a 3D UI (and that I'm on AC power), and doesn't jump up to a higher performance level unless I'm doing something grahpically intensive.
I'm a lot MORE concerned about the lack of other options, though. HD output via DVI has been seriously impacted under Vista. Under XP, I had three resolution options that worked for the TV; 1280x720 (with copious overscan), 1176x664 (IIRC), and 1176x668. These were all set up by the nVidia drivers with the proper timings for an HDTV (not a PC display). The thing is, one of those two strange resolutions (they're both output as a native 1280x720 signal but with a lower desktop res) was perfectly framed on the screen with no overscan and just a little bit of underscan, and the other one (which is the only one I see under Vista) also has little underscan (which is OK), but the whole image is shifted UP by about an inch, leaving a bunch of empty screen at the bottom and the top cut off. This is my only real option for watching anime on the TV though, since overscan cuts off subtitles and softsubs can't be easily shrunk with the image in MPC like the video can be.
So my primary complaint is the compete lack of TV or image placement adjustment options, or custom timings. TV output under Vista just doesn't work properly compared to XP, and the nVidia drivers are to blame!