I had an OFNA .15 engine in my Pirate 10 buggy and it held up well even through my.....ummmmm.....less than stellar rookie engine tuning. That was back in '98, I still have that engine in my Pirate 10 and it still runs solidly. Only problem with it is that the front bearing leaks! (it leaves a ring around the inside of the body after every run) But even with that, it has been very solid and was a great first engine.
So OFNA at least has one good engine.