Black sable tube how good?

I’ve seen these tubes costing double of what some favorable Tubes are costing.
I was looking at the 6922 type.
I thought they made a big difference in my Pro-ject Tube Box phono preamp.  Definitely worth the money, IMO.  I think they used 12Ax7s or 12AT7s.   No experience with the 6922s.  My CD player uses them and I replaced the stock tubes with some vintage Amperex from Vintage Tube Services.  I think I paid about 180 for the pair, but well worth it. 
What makes them different ? Are they just cherry picked , matched triodes with top specs? Are they cryo?  I think I would just trust a guy like Jim McShane or Brent Jesse if i'm going to spend 100 bucks on a 12ax7 or 6922 .....   
Just buy 60s amperex 7308 white label or 60s siemens gray shield from a reputable dealer. If you really want to try new production tube, try genalex gold lion. 
I use a Gold Lion 6922 in my c-j Classic 2SE.... only tube to last long other than Volkshod 6n23eb  in my experience in that pre...   sounds great,  long life.    
The Voskhod 6N23EB is the best value for dollar 6922/ECC88 I've come across - using in Schiit Mjolnir2. Lacks nothing, plenty of punch and extension, tonally tasty.
6922 Black Sable from Tube Depot.  Good tube.  Low Noise, Tight Bass, could use some more air.  They sounded OK in minutes. Back ground was really black after I sorted out some tube rush issues.  Gonna let them burn in see what they can do!!