What's your priority--seeing a specific character, quantity of characters, dining experience, etc.? Some characters are only at 1 of the character breakfasts. We've done Goofy's twice, Surf's Up once, the old princess meal at Ariel's Grotto twice (I think they aren't doing this anymore?), and the Plaza Inn breakfast. I liked the food at Goofy's best, but we had the most fun with the characters at the Plaza Inn breakfast. The Princess meal and Goofy's felt rushed--the characters came up to our table, took a photo, signed their autograph book, and quickly moved on.
Hope this helps!