DD really wants a hoverboard for Christmas. She will be almost 13 by then. I'm very hesitant because of all the problems people had last year with them overheating. And the injury side worries me also. Who has one? Do your kids get enough use out of it to justify the cost? Razor just came out with one last month, $400. Money isn't really the issue. I usually spend this much on her anyway. How dangerous are they?