I've always been told the lower the deck, the lesser the movement. That said, I've always chosen upper balconies except once (because it was a low-budget trip). The one time I had an inside room, I felt claustrophobic and there was a bit of a hum (engine?) I never had in an outside room. I'd personally go for the outside room no matter where it is. If given a choice of location, stay away from rooms very near the elevator/stairs due to noise.
Best to you. Enjoy your trip.