My favorite out of the three is 'Ohana's. Chef Mickey's is very chaotic and crowded for breakfast and it was difficult trying to get all the characters to come to our table. Minnie and Goofy didn't even come to it, I had to track down Goofy, but never found Minnie. 1900 Park Fare is okay and has a variety of characters (Mary Poppins, Pooh, Tigger, Alice, and the Mad Hatter), but I wasn't too fond of the overall atmosphere of the restaurant and I'm not sure why.
For me, 'Ohana's has everything. I also love how it's not a buffet. I'm not a big buffet person and the fact that the food is brought to your table family style is great. The character interaction has always been really good and on our most recent trip, Pluto was making every table laugh by doing silly things. I also love the atmosphere of the restaurant because of all the windows you can see the lagoon/Cinderella's castle.