Actually, I liked Bearcut's post. Hit the mark. As to being any particular makers's apologist, I have said and will repeat, not going there anymore. I note that's exactly what the mods have asked us not to do in this thread specifically.
I really can't pin down a specific knife brand I will never buy. Life has presented me too many opportunities that allow someone to rethink the decision, I mentioned Ruger - but to stay on topic, I'll discuss Buck.
It's practically the quintessential American maker - and they do it all right here. Nonetheless, I couldn't embrace the 110, but adopted the sheath carry until Spyderco invented the clip. I bought a Tarani, found it was a POS, sent it back for QC, and got one just as bad. Figured I would never own a Buck again (there had been others over the years) when a Mayo TNT dropped into my lap for $90. It pays to keep an open mind.
I've never like the Spyderco style, and I've owned one or another since the Gen 1 Endura with integral clip. That exercise in one piece molding didn't work - Sal quickly backed off and went back to metal clips. I've had others, each of which just didn't work out for me - but that doesn't make Spyderco's crap, or put them on a ban list.
I was considering a Tenacious and also saw the Vex. One thing that is guaranteed is that stuff will come from China until some other under employed nation replaces it - like India. As for "Don't buy because," good luck. You won't be buying ANYTHING much for the next decade, specifically electronics. I find it the height of hypocrisy to not buy knives from China while using a computer who's bulk of components are made there. That aside, I chose the BM Vex at a time lots of consumers are not happy with the maker. QC isn't something to ignore - I have no issues with my blade, it's made in China. I bought it for it's features, which I preferred to the Tenacious. The Ti plated blade is still blemish free after 6 months of cutting belting, hose, and boxes. I know for a fact a blade still in the raw with brushed finish would have been indelibly marked by now - and have a lot more surface friction.
I own a SnG, and have used it for two years. The flames are fading, the Ti has wear, the blade still doesn't need sharpening, and it has never failed me. From a veteran's perspective, I understand and appreciate the design because it delivers exactly what is needed in a hard use knife. Does that mean I will never buy a Sebenza? Not likely right now - cash flow is a significant factor - and I have lots of other objections. But they are largely based on intangibles, and have nothing to do with the knife itself. A large regular Classic with rebated blade would't hurt my feelings at all.
I've learned to never say never, and give room for a different opinion. Most disagreements are usually based on the method, not the goal. Makers come up with different ways to accomplish the same thing - cutting stuff. How the blade interacts with the material, even if lowly cardboard, is exactly the focus of a knife. All the other stuff is pretty much fluff to engage the minds of some easily distracted people.