Fuzz is meant to recreate the old 'screwdrivers through a speaker cone sound'. The thing is. You really can't generalize fuzz. It varies GREATLY. The best thing about fuzz for me (besides the sound) is combining it with an octave up or when it oscilates. Both have pleasing results.
Anyways, both those pedals aren't ideal fuzz's. The Big Muff is suitable, but it really isn't a amazing fuzz. It's more suitable as a distortion. Those are ok budget fuzz's though, as is the Dunlop Fuzz Face.
However, if you want to expand your budget for a great fuzz, go boutique. Or build your own.
I know Zvex makes the Fuzz Factory, but he's kind of a douche.
There is the Devi Ever's numerous fuzz's.
Check out BYOC. (Build your own clone)
Monsterpiece also has nice ones.
Fulltone '69 is nice.
Frantone Peachfuzz is as well.
I know BYOC and Devi Ever make some cheap ones.
If you ust want one of the two you mentioned, I say the Big Muff. But it's not really a fuzz.
Hope I helped.
