I currently have my second individual that I've been able to establish. I lost two in QT previously I suspect collection issues there. Both of the individuals I've been able to establish have been good, SPS safe reef fish. Most LPS and all clams have been fine as well. The one I have now does eat some ... well most ... zoas, but it also controls aptasia so it's a trade off I'm willing to make. The first one I had never ate anything as far as corals but I lost him in a tank wide battle with ick.
They do get large, I've seen some huge ones, but it takes a while. They are ravenous eaters, but utilize a tremendous amount of energy as he is by far the most active fish in my tank. Considering he's housed with a yellow tang and a coral beauty, that's says a lot about the activity level of these fish. I have had this one for over two years and it's not 4" yet. It is currently in a 5' long 100g. I would guess it will be fine in this tank for another 18 months or so and then I'll have to move him on to a bigger tank.