I've had a cherub for 1.5 years & it's one of my favourite fish. I found them reef safe (dwarf angels are generally a better bet than mid-sized ones). It was in with pulsing xenias & other soft & LPS corals. When I had a digita frag, the cherub also left it alone.
Cherubs are little pigs & will eat most anything. Flakes, frzen brine, mysis, & blood worms. Lots of personality & spunk. It would take on my yellow tang (4x its size).
Highly recommend this spp. But safest bet is to keep it well fed & slowly introduce corals into the tank. I didn't have any problems with mine but there are always ones that don't read the books about how they're reef-safe
Anthony