Best 6DJ8 tubes?

No G,
I have not...and as is the case, most things audio, it's controversial. No one (too broad) very few deny that certain tools last longer, and that there's a molecular shift in products that have been cryo'd, but many technically oriented (note, I didn't say whether they're experts, as there's no way of knowing)folks openly scoff at the basic concept.
So, have you tried cryo'd G"
Larry

As to 'best'...again, a quick story.
A previous customer, from 1985, called and wanted to hear the LSA system--that is the LSA Statement amp and LSA2 speakers.
Other than the room being 'ugly', I had set the speakers up carefully, yada, yada, and was ready for him.
He's a very good listener, so I knew, for him to be interested, it had to be right, (but mostly, I can't stand it otherwise).
So after listening to a VERY wide range of music, I realized that I had my 'every day tubes' in the unit and not my Amperex. By way of explanation, my audio system doubles as a video--movie watching etc. when I do TV stuff, or again movies. So I keep the factory tubes in, and they're acceptable, expecially for that kind of listening.
I keep my 6dj8, Amprex, circa 8/62 (wow, 48 years old) handy, but FORGOT TO SWITCH! Duh.
So, I said, 'Stop the presses Doc', let me change something. I put the other tubes in, (takes less than a minute), and ice cold, he said "OMG, that's amazing." "What was virtually hard and stark sounding, now sounds rich and much more harmonically correct!"
Of course, he was spot on, which is why I love those tubes.
So...anyone who is more than a casual listener should appreciate them.

Best,
Larry