I honestly believe that feeding a marine aquarium, expecialy a reef requires more of a plan, or program. Than simply one type or food.
For example, for my filter feeders I dose DT's. For my clownfish and and assorted polyps as well as my two tangs, I feed both live brine shrimp, and Emerald Entree, as well as Formula II for a little variety. All thawed and sometimes soaked in Selcon. I also usually feed assorted flakes for midday feedings and try feed my two serpent stars Silversides (little fish). Although its pretty funny. Since the F II has a gel binder the serpent star shoots out and grabs it since it also has krill and brine.
So, I think its best to tailor the food you give to the inhabitants of your tank. A little variety doesn't hurt either. So don't feel that all you can feed is one or the other. First think about the nutritional req. then decide how they might benefit from a change here and there.
Ohh, as far as nutrition. I have found my animals usually respond best to live, as well as frozen. However the tangs require a near constant supply of macro algea. Of which I use Sea Veggies. They work well and sink to the bottom. Flakes are good but can rarely fill the fishers nutritional requirements. So, I would have to agree with Jerry. Frozen usuall works out well in any situation.
Good luck.