I've got 4 hour on my new issue Western Electric 300Bs. I pulled my Sophia Royal Princess tubes that I've been listening to for over 9 years last evening and installed the Western Electrics. I loved the Royal Princess tubes, they never treated me bad.
At 4 hours on the WE tubes this is what I will say. I installed them and they are very quiet, I had none of the clicking and popping some have reported. (I've read almost everything on the web about them) I put on some Allison Kraus as my first listen. They are warm sounding and very open without highlighting any frequency area. The Royal Princess tubes have a bit more punch in the lower base but the WE tubes are more controlled. There is less harshness or edginess from the WE tubes although without having anything to compare with the Royal Princess tubes were just fine. It seems I can hear more of what's going on on the stage with the WE tubes, more dimension of the instruments and performers. Over the 4 hours of listening I played Mark Knaufler, Katie Melua, Frank Sinatra, Moody Blues, Eva Cassidy, Adel and some others. in every case I felt I heard more from the WE tubes. The only qualification I can add is that the Royal Princess tubes at this point are 9 + years old so I would suspect they have gone away a bit. I've had many good evenings with the Princess, no bad feelings or reports. The WE tubes are a marvel to me at this writing. The thing I'm proud of is that the United States once again has a company making tubes.