I have a snowflake in my tank, and yes he is just as the others say. He digs out underneath rocks and is a terror if he gets hungry running around the tank. Other than that he is great, my only problem was one night he decided to eat my cleaner shrimp, that was an expensive midnight snack for him. But I got myself a cleaner wrasse and he seems to love it, so all seems well.
Just be prepared to have to clean up after him every now and then.