I don't use iDine, so I'm no expert. I'm thinking about signing up. From their website, it looks like they have 2 programs--1 for miles and 1 for cash. The cash program is iDine prime. It requires a $49 fee, but you can defer the fee from your earnings. Most restaurants in the program offer a 20% discount, some only 10%. I think the way it works is say you run up a $100 tab at a restaurant including the tax and tip. You put down your credit card and sign for $100. Your credit card gets hit for $100 then gets a $20 refund from iDine. That's how it works if I understand it correctly.

Some may feel differently, but I think I'll take the $20 cash instead of 1,000 miles.