It's not worth it to everyone. I think it's worth it if you like to eat alot in restaurants and you like to have at least one sit down meal a day.
We eat out a lot. We like doing character meals and eating at 50's prime time, Le Cellier, Whispering Canyon, Cape May and H&V for Fantasmic and so on and so on so for us it's worth it.
It's $38 for an adult per day and $10.99 for a child per day. So for your family it's about $100 per day. One sit down meal at Le Cellier can cost more then $100.
You'll get one sit down meal, one counter service meal and one snack per person per day and your sit down meal will include an appetizer and a dessert and drink and your counter service will include a dessert and drink.
You just have to figure out where you want to eat, what it would cost out of pocket and then see which is cheaper for you; the meal plan or out of pocket.
One thing that can make it not worth it is if your child just turns 10 years old because then they are considered an adult and if they eat like a bird, it won't be economical.
Good luck!