Its all about how you setup the bass. Generally a bass tone with no distortion sticks out like a sore thumb in a mix as soon as it is loud enough to hear. Having too much distortion will blend it in too much, kill the low end and make the top end brittle. Its finding the right amount of distortion that is needed to get it to blend but still separated enough to have its own space. The first thing is to have distortion followed by an OD of some sort, into the amp, compressed some more if the amp has onboard compression, and also if available from the amp a limiter, then compress it some more after the mic/preamp to solidify the sound, and thow an eq (to taste), high pass (around 50-60Hz) and low pass (to taste). The big trick is mild amounts of cascading compressors to even out the extreme high and low volumes a bass naturally has, adding an OD to the front end gives the bass the harmonic content of the guitars and gives the bass more aggression while still having a relatively clean sound, which helps the compression even more.