Actually myself personally do not want to be dependent to NOS tubes cos I am worried I like the sound too much, one day all those tubes dissapear, I will be sad
New build tubes doesn't sound too bad actually, at least for me. I heard some old tubes for Darkvoice 337 sound better, like TS 5998, TS 6SJ7 mesh plate, but they are so rare and expensive, I won't bother spending too much money for NOS.
With those new production tubes, I don't have to even worry about turning on and turning off my tube amps cos I know I can get replacement tubes readily anytime, everytime, with the same sound.
I bought mine with additional super charger module installed though. Hope it doesn't make mine obsolete too fast.