Mick responded to my emailed question by citing the worldwide shortage of new production tubes.
In answer to my question about whether he thinks they sound particularly good he simply stated they sound about as good as any current production tubes.
So, let's not over-interpret his use of them. Sounds like if he could get a reliable source of the Russian tubes he's used he'd go back to them without a second thought.
This isn't to say that those who like these tubes are incorrect or that they're not better than other tubes. I think that's the purpose of this thread, is to collect the experience of those who are trying them out.

