I have Shimano cable disc brakes, I think they are borderline crappy grade but they work well all winter. I can ride through water and slush without having to feather the water off the rim.

Be aware that the std rear disc brake position doesn't work well with racks. Some narrow profile brakes can get away with normal racks, otherwise you need a rack with 1" of standoff. That means an extra 1" of wind resistance and 1" less of gap-going-forability.
Chainstay mounted disc-brakes are the ones to get. Scott do this on their hybrids.