As the prices of “NOS” tubes are starting to get silly, has anybody tried any of the current production tubes vs the “NOS” variants?

eBay seems full of dubious “NOS” valves, and prices for ECC83 from trusted suppliers are starting to get silly.
I know that there is a limited supply of good NOS tubes, and there is a high risk that the tubes being sold from some places are either fake, or potentially lower quality stock.

And prices are only going to get worse, so I am interested to see if anybody has tried any of the newer production tubes to see if I should get some more NOS while I can, or if the new versions are good enough.

I am also interested to know if anybody knows of a supplier for PCC88 at a reasonable price.