For me, well I got them because they were $20 and with a little of my time, I could have a fast engine for less that $50. Then the crank issues showed up, and I had written it off as $40 in paper weights.
When Doug found a way to make it better, I was happy, and willing to spend some money. We will see what the lifespan is.
Control line combat with expensive engines is stupid. They crash way too often, that is then only reason I don't have a fora, profi or cyclon. I have Profi and Fora F2d motors, but think 1/2a combat should be on the cheap.