I used them on my 2000 328i and I still have them on my 1999 Vette.
Stopping power is slightly reduced over stock, but not bad for the street. Dusting is nearly non-existent.
The bad thing I have experienced on both cars is with a film building up on the rotors which leads to pulsating braking, like warped rotors. If you drive the hell out of the car regularly, you can at least minimize the film by cooking it off.
After my 328i got rear-ended, I bought an '04 330Ci ZHP. Its a pain to keep the wheels clean with stock pads, but I'm keeping them.
On the other hand, I have Fikse wheels with polished aluminum. Brake dust pits the raw aluminum so I'll live with the light pulsations rather than pitting the rims.
Hope these experiences help you decide.