Of course lockbacks can be crappy, too. I only have experience with Spyderco, Moki, Al Mar and Benchmade lockbacks. None of them ever failed.Well, but I believe the same can be said for lockbacks. There are good ones and bad ones, even from quality manufacturers. Of all the liner locks I've used, Benchmade's has impressed me the most. My gravitator's is the best I've ever used.
What knives failed you out of curiosity?
The liner lock knives that failed were a Buck 880 and a MT SOCOM. And a lot of cheap stuff of course.
It´s just the design principle, I don´t trust. (And mine wore too fast.)