Havent used them personally, but I know someone who has. The airflow is markedly better than slotted rotors. If you look at slotted rotors, they are one directional so they actually spin the wrong way on one side ( cant remember which side ). Check it out but i would highly recommend the roo paw rotors..
Actually, the standard DBA slotted rotors have strasight fins in between the two disc surfaces, so it doesn't matter what direction they are spinning in, they are always spinning correctly. As for the slots, they should always run forward. if one side is not, it means you have put the left on the right side or vice versa.
As for the kangaroo paws, they are supposed to be the ducks guts, but they are hard to get (at least in ACT). I think they are running stocks down of the "normal" sort first.