Hi Steve,
Personally, I've had great success with a minimum of effort (maintenance) with 2-strokes. My First Bully 1.20 I flew for more than 1100 flights with the only maintenance being the occasional plug change. I have not encountered the alleged rear bearing problem with The OS 1.40, but I make sure it is well cooled. Central Hobbies has a deal for the new Webra 1.60 (with the MC carb I think) right now. I've also heard/read good things about the Mintor engines. I'd like one just because I think they look cool. I just wanted to give you a 2-stroke perspective. I've always liked YS engines and wish they'd make a big 2-stroke...maybe someday.
Lastly, I really don't think there are very many 'lemons' anymore - quality control is pretty good these days with CNC machining. I can tell you that out of the box; the OS carbs are set pretty close - the Bully carbs have all been way off - especially the low end.
Happy shopping - just buy one of everything... :-)
-Will