Note5) The Western Electric 1950 Data sheet. says 36 Watt maximum dissipation. Later data sheets say 40 Watt. Though 40 Watt is possible, this is a peak value only, and no normal working point. When you intent to get the maximum out of a 300B, and operate this tube at the limits of safe operation, it is a better idea to use the 300B-XLS in such ... Did you compare Psavne Acme 300B and NOS WE to other 300B tubes? I had WE reissue from 2000x. There are very average overrated tubes. (I know that old WE is a different story.) I have TJ "mesh plate" 300b. They where really not expansive but for my test sounded better compared to WE reissue. I also have EML "mesh plate" 300b.
The EH 300B tube's plate curves and static DC characteristics (plate resistance, transconductance, mu) also exactly match the originals so you can drop them into any vintage or modern 300B tube amp. For the money the 300B EH tube is a fantastic tube! Be sure to read the great 300B tube review and comparison from the Wall of Sound.