Its been said before, but you really have to know how to work with a Rivera. It is sometimes difficult to find your tone in a store with some of the models. I am a huge Rivera fan and I was in a store that had a used M60, the amp was not mint and I could not find a good tone in it. I stopped playing it and switched to another Rivera (Fandango?) and it sounded so incredible, other musicians in the store gathered around to see what I was playing. There was something wrong with the M60, probably had old tubes and needed a good going over. My amp is similiar to the M60 and sounds phenomenal.