At Disney world, it's a joke. Resort guests can reserve rides a week in advance, sometimes the plebs can't even get their first pass until 3-4 in the afternoon.

At Disneyland, it's basically just FastPass. Looks like you still have to be in the park to get a reservation. We went last year and we finished at both parks by dinner time and did everything we wanted because of the Lightning Lane. At Disneyland, I think you also get free photopass too. It was nice to have some pictures with everyone in them.