As a guitar player, bass player and inveterate fiddler, I like to mix and match. Many of the FX in the G3 are also present in the B3, and in an updated form, the B3n, I believe.
The ones I like to mess with are not instrument dependent. In fact, the autowah in the G3 seems to me to sound better than the B3n equivalent, depending on which bass I use. Come to think of it, folk on here who like fuzz or distortion seem to like vintage guitar models, or a Rat or TS9. If it sounds good, it is good..
But of course I have to admit I listen with my eyes as well. Anybody remember Stanley Clarke playing through a Mesa Boogie combo? That just didn't look right to me!