Before you spend a lot of money on the higher priced 300B options I suggest you read everything you can find about the various options. There are so many kinds of 300B tubes for sale at the present that it can be bewildering.
The JJ tubes don't get much respect. But they are excellent tubes. Respect seems to be strongly correlated to price and relative rarity.
Here is my perspective, which I hope makes some kind of sense. Performance is associated with frequency response. Differences in performance are characterized in different ways. A tube with a comparatively upwardly tilted frequency response will be characterized as "more open" or transparent. A tube with a comparatively lower frequency response might be characterized as having a beautiful midrange in which vocals sound amazing. Similar comparisons apply with respect to upper bass and lower bass. I'm NOT arguing that one is better than another or that one tube is superior to others.
I'm sure that the various brands and vintages of tubes sound different. It does seem that those who spend $$$ on the higher priced tubes become cheerleaders for their favorite brand. It makes sense.
But I don't personally know anyone who has purchased and been able to compare the multiple vintages of Western Electric branded tubes. IMHO the current production WE tubes should be considered reproductions, just like those manufactured in China and around the world. I'm not saying they're not great tubes. Those who buy them seem to love them. But I've not read an in-depth analysis comparing WE engraved base tubes to later production and current production WE tubes. Nor have I read an in-depth comparison to Takatsukis, all the variants of TJ Full Musics ("mesh plate", graphite, etc.), EMLs, various LinLais, various Shuguangs, Vaic, etc. All the comparisons I've been able to find exist at a certain point in time, based on the tubes available to the reviewer at that time. These reviews can help point the way. But I haven't read any reviews comparing all the current production tubes. There are way too many!
Also, performance must be considered in the context of a system, circuit and equipment. What choices did the designer make in voicing the amplifier? How did he choose to drive the 300B? 6SL7? 6SN7? 12AU7? What transformers did he choose? How efficient are a listener's speakers? What load do they present to the amplifier? What is the room like? Carpeted? Hardwood? Wall-to-wall? How many bookcases in the room? How many reflective surfaces?
IMHO, none of the 300Bs sound "bad". It is a wonderful tube and current production tube manufacturers seem to have solved the reliability problems. They all seem to last quite well, though in your research I expect you'll run across failures in and out of warranty. Those seem to be the exception these days.
Enjoy your amplifier and the music!
