Re: fuzz or muff
fuzz (assuming you mean fuzz face) can come in many different textures and tones. It gets its sound by distorting a pair of transistors.
muff (assuming you mean big muff) also comes in many sounds and textures. It gets its sound by distorting a combination of two pairs of diodes as well as transistors.
Fuzz faces have no tone stack, muffs have a tone stack.
They are different beasts and have different strengths and weaknesses in their application.
Faces are incredibly sensitive to nuance and guitar volume/tone controls but often don't work well in a pedal chain or if your signal is buffered. Muffs are more predictable and pedal chain friendly, but do not have the subtleties and sensitivity of a face. Faces are very different depending on the type of transistor inside, and how they are biased. Muffs are very diverse depending on the model (ie ramshead, russian, NYC, civil war, opamp version etc...)
Even within the two different types of pedals, you can go through so many variations of each until you find the one you like the best.
Having said that: a useable, tweakable and great sounding pedal that can dip into the territory of both kinds of pedals (without being either), has a wide tonal range and seems to work well as part of a pedal chain is the voodoo labs superfuzz.
IN terms of real world experience, i have done many gigs (and recordings) with nothing but a clean fender amp and a fuzz face and enjoyed it immensely. Due to their sensitivity to the guitar controls you can get a wide palette of sounds. There is no way in the world I could do that with a muff. However, my current (3 pedal) setup has a muff and no fuzz face...so go figure.
Maybe get one of each?
