Charles and I have gone back and forth regarding individual 300b tubes. I prefer the Takatsuki; he prefers the EML XLS (and 213Cobra [Phil] prefers the KR Balloons). However, the number of 300b variants on the market is insane with price ranges from the reasonable to the ridiculous; and there are new ones being produced all the time. IMHO, the specific tube can have a greater impact on the overall sound in an 300b SET based system than one based on an SET using 2A3 or 45 tubes. Unfortunately, rolling 300b can be expensive; but it can be as worthwhile as searching for the best amplifier. And the longevity of a good 300b offsets the cost. . . somewhat.
Gary
Gary