PJC
I'm using a Siemens E88CC gold pin tube and while it wasn't a huge difference it was rather nice. I, too, was shocked by the price of some of these and wasn't willing to part with $75 for it. So I found someone who was selling 3 of them, got a decent deal on them (from ebay, someone I'd dealt with before) kept the one that wasn't matched and sold the matched pair on agon for nearly what I paid for the three of them. So, the one I kept ended up being about $25.