When smmscott and I had our Racoon Butterfly we did have sps and clams....no problems with them, but once the majanos were gone it did pick at the zoas, so we built a little lightgrate box for the zoas. We had tried Joe's, pep shrimp, boiling water, manual removal, but the butterfly worked the best.
Just make sure you get one that will also eat flake.
I recommend Hector over at Tropical Aquarium in brunswick