I fly an older YS 1.20 (the SF - "Big Valve") in my CG Ultimate. I can't imagine a more fun combo! As for your question about the YS engines for an "average" guy, I would not hesitate to recommend one, IF the guy can read directions and FOLLOW them. If a person does that, then in my experience, there is no real "Fiddle Factor" to the YS engines. Many of the guys that I have seen at our field that do a lot of "fiddling" with their YS are running either the wrong fuel (low Nitro, low oil) the wrong plug (stick with OS type "F" or the YS plug), or have been adjusting the REGULATOR (they often SWEAR it is a pump) and needle valves in full turn increments. Sometimes they didn'y look closely at the directions and have the fuel lines hooked up wrong. Often I see all these problems in one engine!

Anyway, this is not to knock other brands of engines, as I own and fly other stuff too. I just wanted to address the questions you asked.

Have fun..

Lee