I have one. I can't honestly say they're more responsive, or if they are it's not all that noticeable, though when I first got it, it was really fast, I guess I've just adjusted to it. The thing I like the most is it tracks on virtually any surface, from wood to cloth, so there's no need to buy those expensive mousepads for good tracking.
Heh, Computers... I'm back, yo! Be gentle!