I'm in a stoner rock band (think QOTSA, Nebula, Kyuss, Dead Meadow) and i need a fuzz pedal, should i get an Octavio Octave Fuzz, or a Big Muff?
One fuzz pedal isn't going to be that much different than the next. I personally prefer the Big Muff, think it sounds huge with the right amount of gain behind it.

If you've already tried them both, either make a decision based on the tones you get, or close your eyes and go random.
Big Muff would be great, but so would the Octavio. Big Muff is just your run of the mill fuzz pedal, while the Octavio is a Octave/Fuzz pedal which would have it's place to because you can get sonic sounds with the octave that the muff wont do. Might as well just buy them both, you can never have too much fuzz!
2011 Gibson Honeyburst LP Trad. w/ SD Whole Lotta Humbuckers
2014 Gibson Ocean Water Standard Plus
Marshall Haze 15W Head/Cab
Hughes & Kettner Tubemeister 5
Thank's very much guys, I went out and bought the big muff in the end, but as a late Christmas present, my uncle gave me an octavio, (for which I am eternally grateful), but I just can't seem to get it to sound out either the octave up, or the octave down tones, all I'm getting is a fuzzy tone which sounds like a scratched cd skipping if I play more than 1 note at a time. Any ideas on how to get the right tone? (yes I've tried having the fuzz rolled back, I've tried every possible combination of settings)