They are high quality pedals and don't come very cheap. You have to be into fuzzpedals though.
Perhaps you read this already on tpdri.com:
It's basically a dirty boost that can go into fuzz territory. Has a nice warm-but-gritty tone to it. Put the Fatness close to full, then dial it back to cut the bass. It maybe adds a touch past 3 o' clock, but if so, it's subtle. Not sure. Output is output, gain is gain.
It's main strength is that it adds a touch of grit and subtly enhances note definition with chords. It's a little dynamic and responsive too. Really nice and simple, and seems like an "always on" type pedal for someone who's not really into using loads of pedals, and just wants a high quality simple dirt pedal for blues, country or rock. And it can give a nicely balanced, textured fuzz with the gain pushed up when required.