Well, a while ago I had an EL34 amp that came with what I was told were cryo'd Shuguangs. I preferred them to a set of NOS RFT's that I bought to replace them. YMMV of course.
“Music has always been a matter of energy to me, a question of fuel. Sentimental people call it inspiration, but what they really mean is fuel. I have always needed fuel. I am a serious consumer. On some nights I still believe that a car with the gas needle on empty can run about fifty more miles if you have the right music very loud on the radio”
Hunter S Thompson