Late to the party here, but will start adding some feedback as well once I've had a chance to listen for a while through a variety of different tubes. Have a couple different sets each of 6A3's (GE; Tung Sol), 2A3's (Kenrad dark glass; '52 RCA), 45 ('40s National Union ST-14), 101D's (stock psvane; psvane WE replica; WE NOS metal base), 300B's (TJ Full Music SE carbon plate) and a few different rectifiers (stock; WE nos 274B; psvane 274B WE replica; nos tung sol 5ar4; bendix 5r4wgb; Mullard CV378 '66) which I look forward to reporting on. Been holding the power tube constant (stock) and trying the others for extended sessions. Spent the most time with the stock psvane 101D's, GE 6A3's, the 2A3's, NU 45's, and just starting to listen with the psvane WE replica which may need some hours on it to break in. Have the 2nd WE 101D coming shortly so that I can use a well matched pair of metal base (omg what is going on w the pricing of these tubes?? is that you guys pushing the market
). The quick summary so far is that the National Union 45's are the most "perfect" and well balanced of all the tubes, sound gorgeous yet have fantastic clarity, extension, separation, and very controlled bass. These are my clear left brain favorites. My right brain favorites so far are definitely the Ken-rad's - sweet, involving, emotional, bass is not as well controlled as the NatU's and not quite the same clarity, but these are "moving" to listen to. Definitely put the psvane 101D (regular) and the RCA 2A3's into a different category, and the GE 6A3's are in between these two categories, leaning closer towards the Ken-rad's than any others. All these tubes are quite well matched (have a tester here for checking). The TJ Full Music 300B's while sounding very good in some amps in the past also did not impress so not going to spend more time with those. Will continue to report back on the others before moving on to the rectifier tubes.
Lastly, YMMV. My system is neutral to lean in the low/mid bass, but very transparent and fast so that will no doubt affect the absolute impressions, so will try to provide relative perspectives as well (Lampizator B7 -> Miyajima Wo1 pre -> ASR Emitter II amp -> modded Quad 57's).