IMO, the best engines for new flyers in the 40/46 sizes are the OS or the Thunder Tiger. Both are user friendly to break in, adjust, and run reliably. The OS has better power but its more $$. It made my training flights less stressful because of how nice the engine ran. I am still running that OS 40FX engine after 10+ years and I don't use after engine oil(we do live in a dry climate though). I have seen lots of problems with the ST brands and some with the EVO brands so as a new flyer I would look at the other choices. In the 60/75 size my personal choice is the Tower Hobbies 75. Its only $5.00 more than the 60 size and is a superb engine in this engine size regardless of its bargain basement price!! It has great power output and its the only engine I will run in my warbirds because of its combination of power, ease of use, and reliability!! Cheers!