This is a pretty easy pedal to use, and there's nothing too unordinary about the controls. There are 5 knobs (Gain, Treble, Middle, Bass, and Volume). The instruction manual isn't very helpful, but that's mainly because the setup is not at all complicated. Its easy to mess around with this pedal and get different levels of distortion.
I use this with a P-Bass primarily, though I doubt it's the best bass for this pedal. This thing is not exactly the tone that I'd be looking for in a bass usually. However, I've seen a band where the bassist used this with a Warwick Bass (not sure exactly what model) and a Hartke amp, and he really rocked it. Granted, they were a sort of punk/hardcore/alternative band, where the bassist literally had to carry all the low end and rock pretty hard at the same time. If that is what you are looking for, by all means, this will work. It will also work if you need something a bit lighter but need a bit more crunch than your clean tone. However, if you need the punch and clarity of your clean tone, be prepared to sacrifice it with this pedal, as it sort of mellows the bass sound out while making it distorted and thick. I think that this pedal isn't the greatest I've ever heard in general, but it's certainly respectable. Its not my style aesthetically, but its an effective pedal for those whose genre/style of music demands some heavy bass distortion.
I don't really like the sound of this a whole lot, but I recognize that many people will. I think that they are actually kind of hard to find right now, so I can't say that it's going to be worth what you might end up paying for it. I do know that I wouldn't pay too much for it. Again, it robs me of too much pop and punchiness. I need the overdrive not to swallow all the character of my bass. This doesn't really satisfy me in that way. Therefore I'd be better off with something else.