More importantly in my opinion, you should also be asking what is the best cruise line for you two. ....some are pretty wild.....some with lots of kids.....some more staid for an older crowd. Food can be excellent or lousy depending on cruiseline. Size of the ship is important too. Some of these floating cities are like living in a crowded city. My wife and I like outstanding service outstanding food, nice clean room, good entertainment,a moderate size ship and not a lot of children running about. Celebrity Cruise lines are at the top of our list.
PS: I'd vote for the eastern Caribbean cruise. Over the western route.