Side bass is cool, I've been using a slide off and on for as long as I have been playing. For starters a slide allows you to play fretless like parts without getting out the pliers [think Morphine], also a slide lets you play way up there in extended range basses realm because the fret board no longer holds you back by it number of frets, you can make weird sound effects; like moans and shrieks, and if you get a e-bow you can play theremin parts.
