It looks to me like these things must be horribly slow and inefficient, but I think it would be interesting to hear from anyone who has actually ridden one. Do they have any advantages, other than being "kewl?"
when i was out garage saling last weekend, a kid at one sale had one. it weighed a TON. it's a real motorcycle wheel & tire on the rear, and that weighs more than my bike all by itself.