I think that this is the service that we used last year. (A sitter came to our room at the WL; it was not a drop-off center.) We were very pleased. The sitter was a grandmother, she brought some small toys with her to break the ice with our son, and she really made an effort to establish a rapport with him before we left. With our permission, she took him for a walk around the resort and to a nearby playground, so they weren't stuck in the room all evening. I didn't even know that there was a playground; she suggested it because she was very familiar with the resort!
A lot of posters on the various Disney sites recommend Fairy Godmothers. DH called both services for info before we left home. He was not impressed by his conversation with Fairy Godmothers; he felt much more comfortable with Kid's Night Out after talking to both.
Hope this helps.