I would not suggest you share a cabin just to get the balcony. I would definitely go with an inside room. There is nothing like having your own space.
If you want outside, the ship is loaded with various types of decks both active and secluded.
Go to the single forum and search for the threads on horrible cabinmates and it may make the decision for you.
(cruzin' solo by design)
Freedom ('09), Imagination ('08), Victory ('08), Destiny ('08), RCCL Navigator ('08), RCCL Majesty ('08), Glory ('07), Liberty ('07), Fantasy ('07), Destiny ('06), NCL PofAm ('05), Fascination ('04), Victory ('04), Fascination ('04), RCCL Voyager ('03), Fantasy ('99)