It's the same as iDine and I think UPromise dining is too. I'm signed up for one of them, can't remember which. And when you sign up for one, you can't sign up for another. It is free. I don't eat at any of the restaurants, so I haven't gotten anything out of it. But if you eat at any of those places, go for it.
You do have to register your credit card, but that's so they can track that you've eaten at the restaurant, otherwise they have no way of knowing. They never charge you anything.
I know my brother signed up through UPromise and I can only assume that he got the money deposited in his account the one time he ate at a participating restaurant.