I don't know if anyone has a story of it failing, although it sure does look like a weak system. I think the plastic gear scares people. Plus, if you know what you're doing, mixing your own ratio is better because you can tailor the ratio to what your needs are. Still, the injection system ain't that bad....
Also, keep in mind if you're going to swap in a bigger carb, I'm sure that most of them aren't going to have a spot for the injection. Another way to blow it up is if the injection port on the carb isn't blocked off well. If you're mixing and it sucks air in from that port, you're motor is doomed!