My all time favorite has to be the MDS .68 (original carb). This engine has 5 years on it, over 200 hours, and continues to run without a hiccup. Only 1 deadstick caused by unbalanced spinner which caused the needle valve to vibrate loose and fall off. Bearings are original and won't be replaced when I install a new liner and piston next flying season.

Oh,did I mention the engine is easy to tune, user friendly, decent power, and only cost 99 bucks new! It has outlasted 3 airplanes......