Organics tend to shed a ton of dust, wear is decent though and they're inexpensive. If you're planning on doing spirited driving, they can fade when hot.
Semi-metallic don't fade as much, and the dust takes some effort to get off, but they usually grip pretty damn well and fade less when heated, but they can chatter when wet or cold.
Ceramics are supposed to fade the least when hot. I just installed a set on my '05 525i...so far, they DO need to be broken in as specified on the instructions (work in heat cycles, or they can eat the rotor face faster) but they give good pedal feel and braking response. They do make noise for the first few cold stops, but after about two or three applications to a full stop, they usually quiet down to silent. I'll see how they do here in a few months when I PCS to South Dakota...not thrilled about that. But, I suspect when they're cold they'll make more noise.