I just got a voda last week. I haven't put much time on it yet but it is fun. It seems much more tiring than just jumping on the tramp without the board. It does make spins more realistic. I can't spin nearly as fast with the tramp board as without. If you've got the extra cash it's worth it for the fun factor I think.
Doug we just got Vodas in Hudsonville but haven't had the chance to try one yet. We'll have 2 tramps setup in GR this weekend. Maybe I'll send one back to Fenton with Steven.