XP has cleartype disabled by default, and 90% of people don't change from defaults, so it will be a new experience for people. I also used to think that Cleartype was bad, as I had a CRT, but it looks much better on a LCD. In my experience anyhow.
I use User normally. I must say that vista makes it much easier, as I got access denied errors with some crappy software, so Vista makes it much easier for me.