i think if i had to pick between the 2, i'd base it on my plans for the day. if i was doing mk, obviously, i'd pick crystal palace. mgm or epcot, then i'd go cape may.
Crystal Palace is a must do for us every year for two reasons: puffed french toast and Pooh and friends; we have never done Cape May Cafe for breakfast, but are doing it this year on a day we are sleeping in before heading off to Animal Kingdom in the afternoon (they have extra evening hours that day).
The standard breakfast fare at both but Cape May doesnt have an omelet station, has blintzes, bread pudding and a huge yogurt bar. Crystal Palace has more desserty breakfast foods, omelet station, breakfast lasagne and puffed french toast.