I have two in a large mixed reef system. I'm going to need to remove them. They will occasionally nip at SPS, but haven't caused any noticeable tissue. HOWEVER, they have taken a liking to LPS and are quickly munching through Euphyllia (I'm losing 2-3 heads a week) and any other fleshy colonies they can find.
They are being fed 3 times a day (2x frozen 1x live brine or live mysis) and eating from all feeds. They will eat Reef Frenzy out of my hand. They definitely need to be fed often.