I read alot of good things about fantoms and I've known O.S. for years, os is reliable but I really don't think they make a serious power house. Sure O.S. gives realistic power #'s but if they're anything like their airplane engines, I would shy away from getting one. They build them to be user friendly, which means you sacrifice power for ease of tuning. I'm looking for a good balance, too much is out of control half the time and not enough is last place in this sport.