We had it for a few years for my daughter. Very bad way to spoil a kid (Too great of a service)!
If a game is lost, you get to buy it... We rented Nintendo DS games (before 3DS was out), we had lost a Mario game, $55 at the time at a local store. We called them, and they were glad to charge us $28 I think it was. I had to talk about cancelling the service, since it was extreme price to pay for a kid to lose a small game. She understood my daughters age range, and understood it kind of ruined our experience with her mistake.
When we moved out of the house, we found the game. It was still $39.99 at local stores (GameStop, and Walmart *not used price though*).
I liked the service they provided, but I play computer games, and they did not support PC games at that time. I'm curious if they do now (I think I seen in a newer commercial, and seemed like they do now)! So it might be worth it to me now if it's Downloadable content rental.