Are you asking if the cashback version is better than the various mileage versions? Or asking if there's another national restaurant network that is better than iDine/RewardsNetwork and somewhat mutually exclusive to it?

I don't participate in this program much anymore, but if I did I'd probably go cashback. Since I'm pretty dormant, I just "accidentally" earn a few AA miles here or there.

I don't think this program has a direct (mutually-exclusive) competitor. Individual cities/regions often have independent restaurants' associations that have some kind of loyalty card...I've had those in a few cities. Plus there are Entertainment-type books for lower-end and fast food restaurants. There's usually nothing that precludes these restaurants from being part of iDine: I know back in the day when this program was more lucrative, I often double-dipped between iDine and a pretty lucrative local loyalty program.

Bottom line in my area: the really outstanding restaurants aren't on iDine. You best shot at a great iDine experience is to hit a really good mom & pop startup. The more established restaurants are either part of a local loyalty program or nothing at all.