They are pricey, but a fine engine. If your looking for raw power, YS is your power plant. If your a fun flyer, and fly moderatly, a OS or Saito will do just fine for the money, but they do not have the pump system. It all depends on what kind or style of flying your going to be doing. I have both YS and OS, and have nothing but good things to say about both of them ..... Greg