I had xp, but when I got a new computer it had vista. It sucked at first since it was so slow. I found ways to make it faster, and it works fine now.
Word! I've installed Vista on my lappy about a year ago, customized it as much as possible but still didn't liked how it works. Downgraded back to XP pro, tweaked it a little bit and I'm more than pleased. I will reinstall Vista when SP1 pops up. I'm not sure it will last longer than previous time though.