Bought 2 in 2003 and DD9 and DS7 loved them. They were old enough to be fairly responsible with them, but not too old... We would do it again.
Going back this fall with the entire family, so we just purchased 3 of the old ones for nieces and nephews. That's still not enough to go around, so we shall see if it was a good idea.
Since I hear they're not available to rent, perhaps there will be fewer of them ("Mom, Dad -- I want one of those!")?