Liner-locks are just fine by me. I like the simplicity of frame and liner-locks. Liner-locks usually make for a more comfortable grip than frame-locks. As long as the liner isn't so thin as to let it bend easily and the engagement is good there is no reason not to trust it. I really don't understand some people's obsession with ultimate lock strength? So long as it's strong enough to wiggle back out of some wood or other material and withstand a bit of an accidental impact it should be strong enough for a folding knife. If you're putting more stress on the lock, (and pivot for that matter) than that, you need a fixed blade or perhaps a pry bar.