People ? which people ? Not the ones I know. I have a ton of 12AU7's and 12AX7's (every type, 5751, WA, JG, A's) and have tried on a variety of systems. Even self built. Black plates, triple MICA. So that's YOUR system and YOUR findings and YOUR preference. One thing I have found out about tubes. You can't label a set or type of tubes as "the tubes". You also cannot discount tubes or assume (as WAY too many people do here) that they must be fakes. All tube preferences are system specific, application specific. They also have to be matched to the links in the chain. So if you have a tube phono stage, tube pre and tube amp, it is much harder to balance than just one of those having tubes. In my power amp, I tried every 12AX7 pair from $10 to over $125 a tube. The final one ? A very rare and hard to find pair of Sylvania 5751 Triple Mica Blackplates Yellow print. why ? detail. My system is very detailed with forward mids, nice tight strong base, wide soundstage. GE and RCA's had the detail, didn't have the forward mids. On my systems, Tele's are DULL. Mullards are sweet (#2). Amperex. yuck ptooy. Bottom line, don't disparage. encourage. If they want to try a Mullard it may be the most incredible tube they one...or ..they may hate it...only their system and their ears will know.