Disk brakes for comps, because if you have to go through something wet your rim brake basically has no chance.
I haven't used dual disk personally, but that seems to be most peoples idea and mine too, because if your rim gets wet with a hs33 it will not work that well. (or as well as a disk would when wet)
I use front disk and rear hs33, I do comps and street, seems to be fine for me at the moment.