I use it on the bass and I was not sure at first because most pedals boost the treble and cut the bass making a bass sound weak, but I tryed the usa bass big muff and the russia big muff and actually choose the russian made over the one made for the bass. it distorts it well for the bass I normally have the sustain and tone at 3 o'clock and the bass volume max for max distortion. this still could use a bit of a bass boost but is not needed I use it with a vintage p bass and a yorkville bass amp. the sound is synthetic so if you are looking for a warm tube overdrive this is not it but if you just want to distort it is great. bassist like cris from muse and I think the guy from queen of the soneage uses it. I also let my guitarist use it with his les paul and ibanez and it sounds great nice deep tone with the lp.
when I first got it, it worked great but then after a couple of weeks the stomp box when activated nothing came out no sound at all. so anyways I like to fix my own stuff so I opened it up and after looking at it a while I noticed a small gauge in the microchip. so I soldered it and sure enough it works fine now. I am positive it came like that so maybe it was just a bad egg. now that I fixed it I would depend on it. it is the only distortion pedal that I use.
this is a great pedal works great for the bass and my guitarist uses it too with his les paul and it sounds great with that also. I actually like it better than the usa big muff made for the bass it is a bit gritter. if it was stolen I would replace it in a heartbeat I will always have one of these laying around.