OK, I've been meaning to get to this, thnaks for the prod. NOTICE: I used the old blue glass tubes, without the black coating inside. These were early production / prototypes, which are no longer available, but are supposed ot be very similar to the final (presumably better) black coated treasures. Using these in a pair of AtmaSphere MA1s, I found the Treasure CV181Zs to be on par with any of the old tubes I have used. I would not say better or worse, and I ended up using a combination of tubes to get the best sound. The Treasures have a nice even response, a lot of resolution, and an airiness. When I loaded up my MA1s w/ 4pair of theTreasures, though, it was too bright. It did take a while for me to figure it out, but adding in some Sylvnia WGT and RCA smoked glass resulted in a nicer sound.
The other thing that might surprise you about these tubes is their size. They use the same size bottle usually found on KT88s, and are quite impressive looking when you pull them out of the box. Make sure they will fit before you buy them. I stocked up on the blue glass ones, because I think beeing able to see the anode plates and the filament glow is an important part of owning tube gear, and I like the look of the blue glass. The opaque black tubes look cool in their own way, but I like to see inside.