I've had a single-blade JACK for a couple of months now, carrying it daily, and I like it a lot! It has flawless fit and finish and, for this model at least, they've successfully combined modern materials and construction with a traditional form. I chose olive wood scales but you can go for totally modern materials with carbon fiber or G-10. It's rare that I don't tire of the knife I've been carrying within a couple of weeks and rotate to another but, so far, that's not the case with this one.
I received my first one as well several months ago. Brother-in-Law in Olive wood w M390, drop point and wharncliffe. Very impressed for the $ with fit and finish. Fills a nice gap in my “office stealth” carry rotation.