Ceramic vs semi mettalic pads
 

Ceramic: These are composed of ceramic fibers, nonferrous filler
materials, bonding agents, and possibly small amounts of metal. Lighter
in color and more expensive than other brake pads, ceramic pads are
cleaner and quieter, and offer excellent braking characteristics
without wearing down the rotors.

I have heard from some other sources (distributors for performance car
parts) that the clients that typically buy speed parts say that the
ceramic pads actually wear the rotors worse than semi-mettallic and
have worse brake fade under heavy use conditions. They say the brake
dust just looks like it is less since the dust is a lighter color.

Does anyone have any experiance on the 2000 a4 1.8T (non quattro) with
vented/slotted rotors between using ceramic or semi-mettalic pads?