Having been on both ships twice with another upcoming cruise on the Allure, I do not think that there is much difference between the two. For us we prefer the Eastern itinerary. Hot dog vs doughnuts, Chicago vs Hairspray no big deal. Other factors besides itinerary that help us decide which ship is staff. Over time we have come to know various casino dealers, bartenders and concierges. Although this is not an overriding factor we do give it some consideration.