Yup. My mom was crazy about getting one. She thought it looked like a lot of fun, and would be easier than putting on/taking off rollerblades (she rollerblades to work often, and not the stupid 80s type rollerblading - she plays hockey).
She bought a used one from a place that had a 30-day money back guarantee, at somepoint during the summer, and I got to use it a fair amount when I visited. I found it pretty fun when you're going downhill (of course). On flat ground I could get it moving pretty well, but it was very inefficient - I had to work a lot to get it going at a fast walking pace. Up hill was almost impossible. I know how to rollerblade, skateboard, ski, snowboard etc, so the motions were pretty natural. I think I could have improved with it a bit, but not much.
Also, it's huge. I thought it'd be a little bigger than a Razor scooter, but it was massive (~5ft folded).
Jennifer Aniston and Brad Pitt bought 200 or so for their friends (that's her picture at the bottom of the page).