ᐅ Which material is best for a light cove?

I would like to have light coves installed in the living room and bedroom of my new build. However, they are available in styrofoam, rigid foam (?), HDPE, aluminum, standard drywall panels, and so on. Everyone naturally claims their material is the best. What is actually the "right" material for this? And does it need to be installed before the interior plastering or only before painting?