Not one fish but Genicanthus Angelfish in general are incredibly underrated. They get big so they require larger aquariums which for sure has some part in their lack of popularity but they are absolutely a perfect fit as a big fish that is perfectly reef safe, while other large fish are difficult at the very least. Tangs are finicky, Foxfaces are prone to nip and get very big, other Angels are very prone to nip. The only other large fish I know of that can compete with the Genicanthus is the Pyramid Butterflyfish.