Some of my Muscovies also prefer to roost but most just lay in the duck house, i think mostly because they're too heavy to fly up to their roost. But, Muscovies are known to roost quite often, even up in trees.
My regular ducks will not. They are not capable of flying, and I think only ducks that can fly may try. It really depends on the breed. I have mortar/concrete pans on the floor filled with pine wood shavings. Usually two ducks take one pan. The pans are easy to clean.