Cindy is completely right. Sun corals are not really hard to keep, they just require a lot more attention then most other corals. they do not rely on zooxanthellae for a food source or energy. This is what seperates them from most other corals. Instead, they need to be target fed about three times a week. Also, a "colony" of these corals are actually several seperate animals living in close proximitry. Thus, each individual polyp needs to be fed in order to survive. This is one of my favorite corals, as long as you are dedicated to taking care of it, it should do fine for you.
Some people are like slinkies...they serve no real purpose yet can still bring a smile to your face when you push them down the stairs!:p
Have a great day! Brian