for microphone and instrument... for bass and guitar? i'm no techie... but that thing's got to work on quite a wide range of frequencies innit? *shrug*
anyway, just an input. i own a sansamp, and like the mxr (according to litford, since i haven't tried one myself), and it does colour your tone as well. I've read a lot about it colouring a lot of your tone, but i feel it colours it just nice, to make your bass sound "fatter"/tube-y/i'm-bad-with-describing-tones, without taking away all of your playing dynamics. If you feel your bass needs more presence in the band setting, u can dial up something good from this.
Amazingly, i haven't touched the overdrive function of this thing... yet. heard good things about it tho.