I've got nothing against the Mesa pedal, I'm sure it sounds great . . . but there was a time where you couldn't throw a mic stand in a music store without hitting a half dozen terrible sounding starved plate toob mic preamps. It really soured me on those low voltage tubes in stuff.
Many had LEDs strategically placed behind the tube . . . y'know. For that realistic tube tone.
yep, that's what matters -but to GuitarStv point, that 8-10 year period of just throwing in a 12ax7 in everything was funny.... in it's time that Mesa pedal made a ton sense however.... I would argue that now it probably doesn't make any sense if your making a new pedal now -as I have three modern overdrive pedals that can be set for tube sag, compression and warmth to perfection -but in it's time it sounded good and still does.