I like the Dynamite .21XP. They perform a whole lot better than I expected. controllable power, average mileage; and easy to tune. I just wish dynamite would eliminate that friggin mid-needle. It scares me to death when someone comes up to me and says,
"Could you take a few minutes and tell me what's wrong with my engine? I've tried adjusting this needle on top, the idle, and I've messed with this big one on the side but can't seem to get the tune right."
OH NO!! LOL. But the XP engines are working great for a whole lot of people I know. Off-road and dirt oval(torture testing.)