Argi complex, Golden, Fisher's, and Pacific Pygmy are the best choices for a reef. Golden probably has the best temperment too. With that said, I have a Lemonpeel in a mixed reef, and up until about a month ago I'd have said that she's been a perfect angel for the last year. Now she's picking at just about every coral I have and she's kinda pugnacious. Live rock is nearly a must for any dwarf angel, at the very least some really broken in base rock (in the tank for over 1 year). They're all hit or miss, but it's to the degree they are reef-safe. I've done Flames, Coral Beauties, Cherubs, Lemonpeels, Potter's, and Half Black Angels over the course of the last 10 years, and IMHE the cherub is the closest to being reef safe out of the lot.