That is why I bought the ax8, but for live use, not tracking. I play guitar and bass, and wanted an all in one unit. Funny thing is, I've mostly worked up guitar parts because my bass needs aren't that hard to put together on the ax8.
For bass, I've used mostly citrus 200 bass . And the bass 400, add compression, drive with the mix turned down low as a footswitch. I keep the cab sim off because I go into the return on my gk fusion into the cab.
There is a separate section in the forum for bass and other instruments. But, so far, it's pretty impressive....