I've always been very happy with the Restaurant.com service at their end (e.g., customer service, order processing, etc.). But, I've had mixed/ambiguous experiences at the restaurant end. At a local Thai place, the owner just went off on me in front of a crowded room when I presented the cert. The gist of it was he felt terribly abused by them and wasn't taking them any more and lost money, etc. etc.
I chalked this up to his perhaps not really understanding what he had signed up for, and then having this endless stream of certs. coming in making him feel terribly beaten up. But it did make me wonder about their sales approach on the restaurant side. Especially with small business owners who may not have great English skills.
Service-wise, I haven't noticed anything, though that may depend on particular places. I've used mine at LM, Dawali, Tratt. Roma, Fattoush, and a couple of little places on Bway that I can't recall, among others, with no noticeable falling off in service.
"Strange how potent cheap music is."