I have an ASP .61 and I really love it. It's not a powerhouse by any means (I have a Y.S.63 for that purpose) but on my scale cessna, it's just right. But then again... it's a 4-stroke. If you are talking about 2 strokes, I wouldn't have a clue. But those 2-stroke engines from China seem to leak quite a bit and a lot of my friends running them have to literally throw in the towel to get them to stop :-)