It looks a fun car, but with wheels and tyres that thin, and just one rear wheel, my main concern would be traction in the corners. My second concern would be crashing it after running out of grip. Grip and safety are very important for a spirited driver like myself.
I've never seen one IRL. I'd definitely try one out, not on a hill climb where I could skid off and down a mountain, but I'd like to try one elsewhere.