@charles1dad , @hddg and anyone else who is interested.... hope this summary helps. Reach out to me if you have any questions!
I was fortunate enough to be able to pick up a lightly used pair of the Psvane WE300b replica tubes. I don't think they have more than 100 hours on them when I got them, and I prob put another 50 on them? Maybe?
Initial impressions are highly favorable! Keep in mind this is a direct comparison to the EML 300b-xls which are my "go-to" on my Coincident Frank mkIIs.
First the spoiler: Neither the EMLs nor the Psvane are substantially better than the other, just a little different from each other, and this is in the context of my system, fwiw. Both are excellent, both are worth their $$ which are more or less in the same ballpark. For me, at this time, I am now leaning a little more to the Psvane voicing over the EMLs in my amps.
On to the details: The tubes are very similar in terms of speed, soundstage size (in all directions, honestly), transient response / dynamics, noise (or to put it better, lack of noise), and PRAT; I highly doubt I'd be able to pick the tube based on these criteria in a blind test.
The biggest difference I hear is that the Psvane is slightly warmer than the EML, and midrange tones and voices appear to have just a little more of a 3D presence, and fullness to them, with less stridency. @hddg is spot on above with the midrange quality of the Psvane!
The EML wins slightly on detail, though the Psvane is no slouch by any means. The bass on the EML is tighter, more detailed as well, while the Psvane is again, a bit rounder, but still fast and certainly acceptable. The highs are not terribly different either, but maybe the slight edge goes to the EML. Too close to really tell. Both tubes present an airy soundstage and highs, but I think the Psvane layers the soundstage a little better, and little more naturally than the EML.
There is no right or wrong answer here. Both are great tubes, both have great instrumental and vocal tonality, and depending on your system, one can certainly be a slightly better match than the other. I have never heard a true WE 300b tube, but man, they gotta be really, really good based on what I hear from this replica, which I am sure is only what, 80%, 85%, of a true WE? More? Less? I dunno, but I am happy with both tubes, but I am especially pleased with the Psvane WE300b replica, and they have been promoted as my "go-to" power tubes on the Frank mkII monoblocks.