While note exactly Groove Tube quality, or Hermida Audio, these are as good as it gets too. The preamp kinds of tubes like AT7/ECC81 are bread and butter of tube amps, and no fancy matching or hot-rodding these.
I've kept mine in a Fender Twin since 2011 and has yet to hear or detect and wear. Running daily. It's the power tubes that wears down first, these one takes ages before anything serious happens. Very silent and very low noise. Would buy them again.