We went two years ago with a 19 yr old (girl), 10 yr old (boy), and two 5 yr olds (boys). We ate at Crystal Palace for lunch (Pooh, Tigger, Piglet), Cinderellas Castle (Cinderella sprinkled pixie dust on the little boys), and at The Garden Grill at Epcot (goofy, chip/dale, pluto). They loved all three. We are going back in a few weeks and when I asked the little boys (now 7), where they wanted to eat again, their first reply was Cinderellas castle, then the Garden Grill was next. There is alot to look at in both places they recalled, so they were both good choices for small/active children.
The other favorite was the sci-fi dinner theatre. I've seen several reviews that they didn't like the food, I thought it was great.
The dining plan was well worth it for us. I stopped counting up the receipts after we were over$1,100 in food for 5 of us.