The kids clubs are sort of like the ones on the Disney ships. They have programming staff there, dinner is offered (included as well I think), they have crafts, video games, toys and movies. We've used the one at GF which I believe is closed now and the one at Poly, which maybe be closed for renovation now :/. Beach Club has one and I believe AK, maybe WL but I think that one may have closed too. The prices I felt were comparable, somewhere around $12 per kid, per hour.
At the club they give you a pager in case something happens as well as taking you cell number. DS is a peanut/tree nut allergy and we've never had an issue there.
I think with the babysitter services, they would take them to the parks if you wanted but I think you have to pay for the sitter's admission. And they service won't give baths.