Crank your Mesa Mark V:25 - I mean really crank it - to the point that it can no longer go louder, just more compressed. And start playing with the dirty channels and the EQ. There are an unlimited number of fuzz tones to be discovered there - exploding Mesa fuzz... I could have never discovered that without an attenuator. Even my Marshall JVM 1 was too loud at 1 watt - I could get the really good tones out of it with an attenuator only. Marshall Mini Jubilee - definitely benefits from the use of an attenuator - that's the only way I can get EL34 breakup goodness. I think attenuators expand better tone possibilitites more than they suck tone... With the wattage I have experience with at least: from 1 watt to 25 watts. 100 watt amp attenuated for bedroom levels? - Yeah, probably not!