What I prefer is not having to actually mod my amp
and then spending a gazillion man hours researching and spending the big bucks for NOS tubes only having to wind up sending them out to have them tested and evaluated.
I'll take 'flat and undefined' against your investment any day at a gig and we'll see how many come up to you and say omg, your tone was SO much better than that guy!
Ain't gonna happen. I have a very critical ear and the JJ's hardly sound flat and undefined to me
Sorry I couldn't ignore the JJ statement.