All I can tell you so far is that there are nearly 100 hours on the engine with no trouble whatsoever. Fuel consumption is right around 4.5 gph and it consumes barely any oil at all. It's as smooth as any Rotax I've ever flown behind and there's no indication that it'll be any less reliable. I'd fly behind one any day.
this was the reply when i asked this bloke about the zonshen , going very well so far.