I've used bobbins, and frankly they're kind of a pain.
Kaffe Fassett--the king of colorwork--recommends leaving long strands hanging off the back. If they get tangled, and they will, you can slide them out one at a time.
Bobbins do twist around each other, and having to unwind them in a middle of a run of stitches gets annoying. I'm not saying that they're useless, just not essential for color work.