We liked O'hana's family style breakfast. Also, we want to try Garden Grill breakfast (we've done dinner and not breakfast). Plus Cinderella's Royal Table is plated and Akershus too (they have small buffet of cold items). If you have princesses among your kids, those two might definitely be worth looking into! The other one is Trattoria on the Boardwalk which is new and has plated options. You can meal Flynn Rider and Rapunzel plus Ariel and Prince Eric.
I would go with what works best for your plans of the day, is easiest to get to in comparison to where you are staying etc. The buffets can be a pain but the variety is great and my kids always love refreshing their plates and trying all the offerings. It also helps break up the meal when kids get antsy, someone can take them up to the buffet and also, you pace the meal whereas plated you are waiting for someone to bring you food. Sometimes with kids, doing the pacing yourself is a good thing!