Haven't been, so maybe other can comment...but I hear Fresh Mediterranean Market at the Dolphin has a really good breakfast buffet. If you don't want a buffet I would probably say Kona.
Last trip my DH and I had breakfast at the Captain's Grille in the Yacht Club. You have the choice of the buffet or sit down breakfast and no characters. We chose the buffet and it was very good.
Kona is our favorite. For a non-character buffet we like Boma - be sure to have the Frunch.
We've eaten lunch at Grand Floridian Cafe twice and both times the service was very slow. We've avoided it for breakfast because the last thing I want in the morning is a slow start to our day.