Windows Terminal Server
Easy to manage, doesn't crash easily and if your users log off correctly, they won't get hung sessions which will force you to clear them off.
Basically if XP worked as well as WTS 2003 does (and it doesn't and it's no where close), there wouldn't be an issue really. Just my experience.
Well, that's one OS I've never used. But isn't XP geared more toward desktop use while this WTS, form what you are saying, is a server. How can they be compared?