Agree with Eric. I bought the skate-styled one (with the kick tails), and have since made 2 others to add to my Indo quiver, (one is shaped like the original, the other is what I call a mini-Squirt). I love messing around on them, I've recently learned how to do crossovers without killing myself (or taking a chunk of drywall out of my wall).
As far as it improving your riding, it does help, a ton. You may not notice or realize it, but it does. I also like to do core exercises on them with weights, like Adam.
If you have the money, buy one. You will use it for years.
Note: the above is not the one I made. It's my friends Indoboard, who turned me on to them.
(Message edited by craiger on October 21, 2005)