i would have to go with ys as I have had os and saito, and magnum also, none compare to the ys, i have probably about 200 or more flights on this engine and i have only had 2 dead stick lanings, both times i ran out of fuel. the power is awsome also, i have the 120fz and its more power than the saito 150 i have flown. It cost more than the others but definatly worth it.