Do you have top end hardware? I bought a Vista machine from Dell (Athlon 64X2 4100+,2GB Ram, 7200RPM SATA, 6150LE Nvidia), and it stutters audio on DVD playback, and is generally mush more sluggish than XP SP2.
Also, UAC takes a looooong time to come up sometimes, delaying program starts dramatically in some cases.
I will say it’s only BSOD’d once (despite 100% signed Vista drivers!) compared to XP SP2 having a BSOD every other week (flaky hardware, but impossible to pinpoint which, bad exception handling?).