I have Sonic CD working in Vista both the old Windows 95 game and the ISO of the Sega CD version, but neither of them work right. The Windows 95 looks like crap because it's at 640x480, 256 color (which I have to switch to every time I want to play it), and when I go fast, lack of vsync makes ugly waves on the screen.
The Sonic CD for Sega CD that I have for Kega Fusion allows me to run it at 1440x900 (my laptop's native resolution) without forcing me to go to 256 color and has vsync and looks really nice, but the music is completely different and I really don't like it... >>