#2
It's a Boss MT-2, not ML-2. And I don't play deathcore, but I really like the metal zone for other kinds of metal. The Metal Core is a bit too "loose" in it's distortion (or muddy if you like). The MT-2 is alot tighter. There's demos on the boss website though.
#3
They are awful sounding pedals. Serisouly, dont buy either.
Gibson Les Paul Custom
Fender American Tele

F/S:
Orange Rockerverb 50
Orange PPC412
#4
+1
Gear

Standard Epiphone LP W/Dimarzio Super 2's
1973 Ampeg VT-22

Fulltone Clyde
Ernie Ball VP Jr
Boss tu-2
Boss sd-1
Ehx Little Big Muff
Fulltone Ultimate Octave
Boss eq-7
Ehx Memory Man
Digitech Delay X-series
Ehx Holy Grail
#5
I used to have a Metal Zone and I was satisfied with it for a while, but the tone began driving me nuts so I traded it in for a Boss MD-2 Mega Distortion. While it isn't perfect, it produces a lot more low end than the Metal Zone. The MT-2 was just too "tinny" sounding... I could never get it to be ballsy enough. I don't have any experience with the Metal Core though so I can't really comment on it.
Axes:
2010 Carvin ST300C
1994 Jackson Soloist XL Professional
2008 "Jacksbanez"
2007 Gibson Flying V
2003 Epiphone Les Paul Plus

Amps:
Peavey 6505+ Combo
Peavey Classic 30
Peavey Vypyr 15
#6
Get a Danelectro Cool Cat Metal II instead. Seriously, I'm not kidding. It's about 1/5 the price and it's quite similar to the EHX Metal Muff.
#7
nothing really touches the metal muff, maybe a smart people factory - red threat, its a sick distortion pedal
Gear

Standard Epiphone LP W/Dimarzio Super 2's
1973 Ampeg VT-22

Fulltone Clyde
Ernie Ball VP Jr
Boss tu-2
Boss sd-1
Ehx Little Big Muff
Fulltone Ultimate Octave
Boss eq-7
Ehx Memory Man
Digitech Delay X-series
Ehx Holy Grail