Ive been trying to keep up with these things for a while. They are def. pretty cool. As far as the rollovers...think about how easy a roll on that extremely loose sand would be compared to a complete roll on rock. I would rather roll 5 times in the sand compared to 2 good rolls on the rocks.
I'd love to drive one of those things. I doubt I'd look impressive, winning those competitions takes a great driver and a great machine. However, I'm sure I could put on a pretty good show.