RE: Engine shoping
The most USER FRIENDLY engines I have encountered (highest price to lowest ) are OS 46 FX/AX, Thunder Tiger Pro 46 and the Evolution 46.
For long engine life on ANY engine, follow the manufacter's breakin instructions, use a fuel with some castor oil in it (usually referred to as a "blend" - the castor helps prevent damage in the event of a lean run ), ALWAYS run the engine SLIGHTLY rich (to avoid a lean run ).
When done flying for the day, drain the fuel from the tank, THEN start the engine to run out any fuel left in the engine. Use after run oil (Marvel Air Tool Oil is an excellent alternative ) to prevent/minimize any corrosion of the internal parts (Glow fuel attracts water/moisture which will corrode/pitt the internals of an engine, especially over the non flying season (winter ).
The above procedures will normally provide many YEARS of use from an engine. I still have a couple of engines that are over 45 years old and still run great (Super Tiger/Como 19 "Racing Engine" (one of the early ball bearing engines ) circa 1958 and a McCoy Red Head 35 circa 1959 - 1960 )