2 ships. 2 cruises taken a year apart (Carnival June 2014 & RCI 2015). Same port (Galveston). Same destinations (Cozumel, Grand Cayman, Jamaica). Both family vacations with children ranging from elementary age to college age.
Cabins: Navigator of the Seas had slightly more spacious cabins (balcony). Nothing huge, but noticeable.
Main Dining Sitting: Carnival Magic had a more lively atmosphere. Food tasted about the same. Wait staff worked equally hard and was attentive on both but I'd lean towards the Magic.
Only got off the ship to look at the new port. Clean and friendly. Shopping has the normal tourist stuff. However the food at the restaurant is outstanding.