I was on the elctro harmonix website and I saw the double muff, I have never seen this before. Have any of you used it. and how would it be for classic rock, same for the Big Muff?
I used it and I think I like the regular big muff better, more tonal options. It is an excellent choice for classic rock though, but it doesn't have much more gain than the original.

Ibanez S370 (all custom)
Mesa Boogie Studio Pre
Fender Champ 25se (used to power Mesa pre)
Custom 2x12 cab w/ Eminence Texas Heats