I am working on planning my honeymoon in July 2011 and we were looking at either the Explorer of the Seas or the Caribbean Princess out of NY. We are in our late 20's and having a tough time deciding. They are both 9 nights.
-Royal Carribbean goes to Kings Warf, Bermuda; Philipsburg, St. Maarten; Charlotte Amalie, St. Thomas; and San Juan, PR
-Princess goes to Bermuda(west end); San Juan, PR; St Thomas, USVI; and Grand Turk, Turks and Caicos
I have found out that Kings Warf and West end are the same ports.
If you enjoy a bit more active ship, more activities, I think Royal Carribean would work nicely. Princess is more laid back, not as much to do on the ship, slightly better food, IMO, but entertainment is better on RCL. All depends on what you are looking for in a ship and what you enjoy doing, etc.
personally i like Princessess itineary better. I think that the service and the food is better on Princess, especially like the idea that Horizon Court buffet on Princess is open 24/7, and that the pools on Princess ships are fresh water. RCI had the edge when it comes to live entertainment