I've been running tubeless on my hardtail for about a year now. My setup was Mavic XM 317 rims (non-tubelss) and Kenda Small Block Eights (tire with fairly thin sidewalls). Only flat I ever had was a cut in the sidewall during a rocky downhill portion of a race (still have scars from that one). Definitely worth going tubeless to avoid the hassle of flats. Can't tell you how many times I would have had a pinch flat after hitting some rocky terrain if I hadn't been running Stan's. I wouldn't even consider doing an endurance race without running tubeless.