I have a ZDZ 50ng and DA 50 which are both great, easy to start, tune, and run great. My 58 ran great, and had no problems with it what so ever until it ate the piston ring after 5 gallons of fuel.....still running 32:1 break-in. If horizon had not sent me a non functioning engine 3 times, I might still own an Evolution......I am not dissatisfied with the engine, merely the quality of service.