I purchased a Meerkat 440C in PE, and whilst the lock is indeed very unique, that is once I figured out how to close the knife, there have been unfortunately several flaws with ther Meerkat's, not just mine but also as stated by others.
The locking liner has been loose on several member's knives which I have heard of, and many have had a fair amount of blade play. My personal Meerkat has the opposite liner that is loose, and the stainless steel liner is actually crooked, with the blade experiencing a gread deal of play both vertical and horizontal. The locking liner is also fairly susceptible to breakage IMHO. I assume that these inherent issues may have led to the Meerkat being discontinued, even though it appeared to be a very cool knife, and I do like mine, it's just that I do wish that the quality was abit better, and that at least it was properly functional, although it was a much cheaper item, and for the price, it is in my mind a "must-have".
So all in all, whilst the Meerkat is indeed a cool knife, and the Phantom lock is very innovative, and quite cool in it's uniqueness, I think that it is more of a novelty, rather than a practical feature, and thus I don't honestly think that incorporating this locking mechanism on a larger knife would be all that effective, in terms of a larger knife needing to be more robust, and able to withstand heavy use, and to hold onto a liner that moves, is not very sturdy to me, and the overall design of the lock seems vulnerable on a larger knife which generall is used for utility purposes, self-defence and whathaveyou.
Although if the design of the lock were midified and maybe updated, and the flaws solved, it would indeed make for a cool feature, however I simply see it as a feature only compatible with smaller scale knives, and definately not a larger knife which is generally used for utility purposes, as well as self-defence situations.
This is just my view at this point in time, and much of it is derived from my experience, and the experiences of others as stated in their reviews, of the Meerkat.
