Can't add too much, I had a Ryobi 2 stroke I liked that was basically fuel, plug every other year, clean the air filter every year. I forget what happened to it, but I bought another Ryobi and I don't like it, NO air filter and the carb cover flies off if you hit the choke lever a little too hard. Somewhere on here is a post about single bearing (think the old Cox .049 model airplane engines) and two bearing engines. Apparently if the starter is on the shaft side of the engine it's likely a single bearing. As I've said before, I old enough to spend a little more for what I really want and given my local dealer that is excellent, I'll likely buy a Stihl or Echo, whichever feels better (they sell both).