I bough about 6 tubes for my two tube pedals and one mic preamp. Compared to the others (the six new tubes + the three stock ones), this one's output is really weak, it's gain is soft, compared to the others. I don't know whether this is how it is supposed to work, or it happened I received a faulty one, just it does not behaves as the advertised JJ - "high gain".
Other than that, its sound is good, clear and smooth, no emphasis on narrow bandwidths. I am currently using it on my tube mic preamp, which is a loud device, this valve tames is a bit and I see this JJ well fit for this purpose.
As a minus with the service, all the tubes in the package were just thrown in, and their boxes were found smashed on arrival. The tubes inside were intact, though, I could find no noticeable defects.