I first signed up for this service as "idine" with my Chase Perfectcard.
I don't pay an annual fee, and I think my membership was free and part of the rewards offered with the credit card.
However, once I had to get the original card replaced due to a fraudulent charge that appeared, I was charged a $10 membership fee by rewards network for the new card number (which they just deducted from my rewards, so I paid nothing out of pocket).
$49 would be a bit steep to me for these kickbacks -- but if you can get them for free or at a reduced rate through a credit card or frequent flier program, its a nice perk.
As a lurker, you can see which places offer discounts, but I don't think you can see the exact percent bonus for each day until you become a member. Most places give you 10%, often excluding weekends.
I was excited to see Calvin's Smokehouse on Armitage was recently added (10% everyday)
Some others that offer more than 10% are:
Cafe Laguardia offers 15% mon-fri
Coco 20% everyday
Pizza Metro on Division 20% everyday
India House downtown 20% except Sat
Le Peep 20% M-F
Kitschn 20% M-F
Fireside (Ravenswood) 20% sun-thu
Pasta de Arte is 15% sun-thu
40% back are "hot deals" and are usually newly added/opened/re-opened places trying to build a clientele and look busy
Currently the hot deals for Chicago are Gunter Murphy's on Roscoe
and Spot 6 Night Club in Wrigleyville -- both seem to be bars/clubs and not dining destinations which is a new category of venue to offer bonuses on this network.
There have been some good destinations in the 40% bonus including Darwins back in 2004.
As noted in the thread on restaurant.com, some of the same restaurants (like Sweets & Savories) offer discounts on restaurant.com, if you get a coupon for 60% off, plus the rewards network bonus, its like they are paying you to eat! well almost