Depends on where your going that day and what characters you like. We did both last week. For me, I'd pick Cape May Cafe because I like the atmosphere and buffet offerings better.
Ohana is good for when you visit MK, characters are Lilo, Stitch, Mickey and Pluto. Breakfast is served in a family style platter of scrambled eggs, bacon, sausage, potatoes, melons and pineapple bread. A server comes around giving out Mickey waffles. They will take your picture before breakfast with flower leis (separate charge of $32).
Cape May Cafe is good when you visit DHS or Epcot. Characters are Goofy, Minnie and Donald wearing beach attire. The buffet offers lots of cereals, breads, pastries, fruits and hot foods. I much prefer their food.
Have a fun trip!