I don't know about Jack Wolf. I tried carrying a Pena for a while.
I like them a lot - think they're gorgeous with good steel and a lovely design. The top flipper took a little practice, but works well. At the time I was mostly cutting many, many zipties, and it was perfectly fine at that.
But after a couple weeks of carrying it clipped to my pocket, the clip screws developed enough play to allow lateral movement in the clip, and it is pretty obvious it will fail at some point. So I stopped carrying it.
Possible that that one had a problem, but I suspect it is just a matter of the design, and me expecting too much from it. It would not the first time; I end up spending time both in corporate meetings and worksites in the same day, and usable knives that don't freak people out is a balancing act.