I have not used them yet, but have a reservation for DD4 in February, made through DisneyDining.
They had different times available for dinner. Based on the drop off time I picked, I had to choose between 6:30 and 7:30 for dinner.
Children have to be between the ages of 4 and 12 and potty trained. According to the Disney website, they have supervised activities, computer games, and Disney movies.
I have not used them yet since DD just turned 4, but everything I have seen has been positive.