We did a different character breakfast each morning of our trip in December and never got bored with it. You may see a couple of the characters at more than one breakfast, but there are new ones at each. Mickey is the main character we saw at several breakfasts and my two girls DD2.5 and DD6 never got tired of meeting him!
It's great meeting so many different characters at the meals. If you don't want to wait in a long line at the park to see a character you will have met at a meal you don't have to unless you just want to.
Our favorites: (1) Tusker House (best food and a large buffet with tons of choices)
(2) Princess Breakfast at Epcot (Yummy family style with the Princesses if you are interested in them) ties with Ohana (delicious family style with really fresh fruit and Lilo & Stitch)
(3) Crystal Palace (nice buffet with made to order omelets with Pooh & friends)
(4) Hollywood and Dine (large buffet with pretty good food, but they really need new characters to replace Jo Jo and Goliath)
(5) Chef Mickeys (our least favorite food, but the big 5 characters)
My kids were excited at the character meals, but I disagree that they don't eat much. My two girls ate tons of food which was great fuel for running around the parks and riding rides. All kids are different and only you know your's the best. As far as buffets go, my DH had one girl and I had the other. We carried 2 plates, sat one down as we got food for one plate, and sat the other down to get food for the second. We had no issues with the buffets despite having a 2.5 year old walking through the buffet lines with us. However, the family style meals are more relaxing and you don't have to worry about missing characters. FYI - if you do miss a character, be sure to tell your waiter and they will make sure you see that character before you leave - you are paying to see all of them.
We loved doing all the character meals. If budget allows for our next trip, we will plan a character breakfast for each day. We got into the parks early, had a great meal, and met tons of characters. That's a pretty good way to start your mornings at Disney IMO!
Have a great trip.