I personally would go with the reef. I really like having corals. If your looking for unique there are a ton of corals that are very cool out there. A huge selection. and as far as fish if your willing to take it slow and save up this is a very cool looking
fish in my opinion that would fit in your 55. This is another one of my
favorites as well. I can't comment on personality or those kinds of things because i haven't owned either either one of them yet but they are very cool/unique looking. I would rather have a few more smaller fish then just a couple larger fish. Makes it look more like a reef community.