My wife and I just came back from a 5 day cruise on Magic. We have been on 12 cruises from the Galveston and Houston ports and have enjoyed all of them. Two months ago we went on the Emerald Princess for 7 days. Emerald and Magic are in the same price range so I will give a comparison:
Emerald goes from the Houston port .....this is a newer, better, and easier port to travel from.....advantage to Emerald for this.
Magic is newer (2010 vs. 2007)
The cabin was excellent!! Larger rear facing balcony....and the cabin seemed a little larger.