What distortion is better :
Electro harmonix metal muff with boost
MXR fullbore metal
(and suggest me some boost pedal)
^^^ +1

also, what amp are you currently running through?
Quote by Led Dirigible
Crickets have too much high end for my tastes. I prefer a nice beetle, lots of warm low end.

tl;dr put a beetle in your amp for superior toanz.

Guitars: Schecter C-1 Classic
Westfeild LP e4500
Amp: Vox AD15VT
^^^ sorry to interupt the guys above but i own the micro metall muff and it cranks out some great stuff, the regular metal muff has a better tonal range and boost than the mico too, but if you have a noisy amp the full boar might be good coz it has the built in noise gate (dont ask me the quality of it though coz i havent heard it.)
I have just packaged up an MXR Fullbore Metal for return as it is without doubt the worst sounding, thin, fuzzy and down right cheap sounding distortion pedal I have ever used.

I bought it as I recently broke my EHX Metal Muff Micro and wanted to try something else, but I will now be simply replacing the Micro Muff with the full blown Metal Muff as the Micro was an awesome sounding little pedal.