As well as guitars track using this pedal, there's really no way to capture how L O U D this pedal is. With the level at 9 o'clock it easily doubles your unprocessed volume.
The pedal sounds like 2 fuzzes running at the same time -- one is very 'fuzz face' and the other is very 'big muff'. There is a lot of note clarity but sick amounts of low frequency response at the same time. The "contour" control (for lack of a better term; it's unlabeled) seems to control the balance between these two tones as well as applies a pretty wicked Q to the EQ curve.
You can't help but laugh as you play with the Fuzz War; it sounds H U G E.
Highest recommendation for anyone looking for a fuzz that's usable for metal and not looking to recreate the sounds of yore.