I have a green open brain (Lobophyllia) and 2 favia brains. I have had the favias for 4 or 5 years, the lobo for almost a year, and have only occasionally spot fed them (by "occasionally" I mean like once a year).
These corals are photosynthetic, but they also readily accept meaty foods. They extend feeder tentacles when the lights go out and thats when they'll accept a feeding.
Most brains do not require a lot of light -- all of mine are at the bottom of my tanks. They are stoney corals so they do require that calcium and alk levels be maintained.
HTH,
Mariner