From Don Sachs whose electronics use 6SN7's octal tubes. He has heard most every variant of the tubes and concludes this:
"In my gear, I use Linlai e series or the Shuguang WE6SN7plus. The best tube I have ever heard is the new Ray tubes select 6sn7, which is pricey." He is believes these Chinese tubes are superior in SQ to a lot of the pricey NOS tubes. He admits that he has not heard the new WE 300b tubes, which might be better, but are extremely expensive.