I've had these tubes a few weeks now. I have not gigged with them yet, and I'm using them in a Bad Cat 20 watt combo. I am comparing them to a few NOS tubes that I was lucky enough to find at a reasonable price. The Tung Sols sound very good, especially if you like a forward mid sound. They do seem to be as clean as most of my NOS, but I still prefer some (but not all) of my NOS because their sound seems more balance across the entire frequency spectrum. I don't know much about tubes, but I've read that their tone changes after they are broken in. Now, I'm only comparing the new Tung Sols to new NOS.