This is like reading the reviews on the guitar sites... Is the Ruby tube better than the JJ? Is the Electro Harmonix better or is the Tung-Sol? What about the Mullard? How good is the JAN Sylvania? How do those compare to a NOS RCA? What tube sounds best for clean tone? What is best for overdrive?
Disclosure: I own two tube based guitar amps, one of which is an old kit I just gutted and am in the process of re-designing...
Punchy lows. Solid mids. But where it really excels is highs. They're crisp and clear all the way to 200GHz and beyond. Of course you'll have to use our superflex cable with gold plated oxygen free copper conductors to really hear the difference!
Disc space -- the final frontier!