I've flown YS engines for nearly 20 years now and I've not had but one engine go south and YS warranty service was Outstanding. Inside a week they had my engine repaired and returned. The engine again gave me problems and one call to YS had the required parts in the mail the next day. Turns out it wasn't the engine that went but my operation of it. I run my YS1.60 on 30% but every other engine I've run on either 15% or 20%. I also run OS engines and they are a fine product as well. Having flown both engines I can tell you the YS wins hands down in the power department.