Yoda, yes this format does have a number of disadvantages the most obvious one being ease of opening and closing, they are not easy one handed openers. However personally I place lock security at the top of my list and the Twistmaster looks to be optomized along those lines.
Dennis, I have looked at production liner locks before from companies with the best reputations for making strong and stable versions. Specifically the Spyderco Military and Buck/Strider folder. It was not difficult for me to disengage either lock, nor even break the face of the liner.
I might pick up a SERE in a trade or something as some of the comments about the cutting ability were interesting, but I have no interest at all in the lock.
-Cliff