Any difference between tubes.

Less microphonics? Huh? I've had dozens of various tube guitar amps over the years and, weirdly, it was only sorta recently anybody gave a damn about the brand of tubes...you just wanted it to work! Now I use matched output tubes (biased properly...who knew?), and carefully select the preamp tubes for whatever their job might be. The latest "fadlet" among guitar players is low wattage all tube amps that get the meat out of the output tubes at lower volume levels...a good thing and I'm right there with a 5/15 watt amp. 5 watts can sing...and be surprisingly loud (for the record...I'm currently a 6V6 abuser).

Yes, ours are more expensive.

That has to be the "Gettysburg Address" equivalent! Excellent. :-)

Viridian nailed it, but yes, they can differ. Audiophiles want tubes with low distortion and noise. Electric guitar players select tubes for their particular distortion qualities after clipping.