Haven't tried marine snow, but I know my corals (cloves, shroom, ric and candycane) appreciate the 2nd day feedings of cyclopeeze powder.
Corals aren't plants, they have mouths for a reason, one cant rely solely on light to make the corals grow - Just like you can't raise fish (well most anyway) on a veggie flake alone; need some variety in food to ensure proper nutrition.
Andy