I just got a Studio (still in the box waiting to be set up), and I'm really curious to see how it does. I love the idea of it; it's specced more than I could get in a laptop, which is exactly what I want for my desktop work.
I never really got the appeal of the Mini, because it wasn't specced much better than a MacBook. The Studio seems to be a nice middle ground between a MacBook and a mac Pro, which I know I'll never need.