I tried it and it wouldn't start up right every time for me so I took it off and went back to Vista Ultimate. I love Vista now. So handy for everything.
I was helping a friend the other day on her computer and it had XP on it, I was getting frustrated because it was slow and not very handy like Vista is. But I got through it.
But if I am still around when they perfect Windows 7, I'll probably see if I can try it. I liked the options on display mode and other cool things about it, the beta version just wasn't stable enough to run well on my computer. And that is odd because Dell's are able to run just about anything well.