Not having eaten at Minnie & Friends and only reading reviews, it seems like the food quality is not usually what gets high marks, but I think it must have gotten better in the last couple of years. It is the number of characters there that is the draw. You will find the most characters at M&F, which can be chaotic for some folks.
Many people like the quality of the food at Storytellers Café (Critter Breakfast) and at Surf's Up with Mickey (at the PCH Grill). I like the food at Goofy's Kitchen -- more for breakfast than for dinner, but dinner was good too. Goofy's Kitchen has the widest variety and largest buffet out of all of the meals, as it is a restaurant that only exists to be a character meal. It is not open for non-character meals at any point, unlike the other restaurants.