The Mudhoney is perfect of you want an all-round distortion and overdrive pedal to suit a variety of different situations. Or, if you are looking for a great pedal to use as your main distorted tone, and prefer a more vintage-type distortion. As it "melts" and fuzzes up a bit at high gain, I perhaps wouldn't recommend this for metal sounds.
I am a big fan of the pedal so far, though I'm still experimenting. I currently use this pedal as my 'distorted' sound, with an overdrive after for solo boosts. On lower gain settings, you can really dial in a balance where you can dig in for more gain whilst having some clearer tone when you play quieter.
It's a unique pedal, I can't say it particularly sounds like one distortion pedal or another - has its own thing going on (at least from my experience of other similar pedals). Apparently it bears resemblance to the RAT, but it seems quite different to that also.
Definitely worth a try!