I've placed about a dozen orders with them, and my experiences have been good.
Searching for the word Bladematrix in TGBU, I was surprised to see that some of the early posts were not favorable. I'd guess that they may have had some difficulties when they first set up their Web site. In my early orders, I'd occasionally order knives that were out-of-stock, but they didn't charge me for them, so it didn't bother me. My last couple orders from them (for Beckers) after Camillus went under, Bladematrix had an inventory database that prevented me from putting any more in my cart than they had on-hand. Their site was good by the time I placed my first order with them, and it's improved since. If I were to find fault with anything, it would be that their pictures and descriptions aren't as detailed as some other Web sites, but their prices are usually much lower.
I've gotten emails from Kendal, and have found him to be great to deal with. For example, one of those early orders included a Becker Combat Utility (BK7) that was out-of-stock; he offered me me a desert Desert Series BK71 for the same price, which I was happy to accept.