I just 'saved' a school of blue devil damsels and their cousins the white/black striped damsel. I have all 10 of them in my 150 right now - alongside maroon clown pair, anthias, tangs, and school of chromis. Surprisingly they are well behaved and rarely fight. Everyone has all of their fins still intact. They never bother my corals, shrimp, crabs, hands, other fish etc.
It was either I put them in my system or they would have went to the big ocean in the sky - so now they are there and I will play hell in getting them out in the future. For now the peace is being kept.