How does the sound of the PCC88 and PCC189 compare to the 6922/6DJ8 and its iterations?

I'm not relying on all-over-the-place anecdotal reports of different users. I'm gathering information from all sources, sifting, evaluating and noting where there is consensus and divergence. Unfortunately the sample size of user experience is smaller than I had hoped.

Vacuum Tube Valley issue 7: the top three choices: Amperex 7308PQ (very dimensional and musical, with smooth balanced highs) - Siemens 6DJ8 (60's West German) - balanced sound, smooth and detailed. This tube does almost everything right. 10M Mullard (60's British) - natural and sweet sound with good balance. Minimal, if any sibilance. For those on a budget, the JAN/Philips 6DJ8 and 6922 are capable of good sound at a reasonable price.

I recommend getting a copy of Vacuum Tube Valley issue 7. They test and report on a wide variety of these frame-grid tubes! And are trustworthy! BTW, I have at least two preamps that use these tubes - an ARC SP6 and a Conrad Johnson PV3. Hence my interest.

Great reference. Thank you!

This is a good source of info: https://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html