I have one over my 20 gallon now, I will soon be adding a second or maybe even a third. I first started the tank with an LOA 65W PC, then added a second LOA. I thought it looked good untill i got my CSL 55W smarlite, talk about difference! It also seems that everything in the tank likes the 55W more then the 65W.
I recently got a Euphilia sp. coral that probably wants more light. It's hard to tell, it seems so healthy!. Either way, It will only be happier with more.
Here are some images of it: