Bob S.

Most of the reviewers with negative comments below apparently have difficulty navigating a web page. Any certificate that ends up not being used (for objective or subjective reasons) can be exchanged for a different restaurant for a "gift card" that can be used at a later date. My experience has been mostly positive, in that restaurants have accepted the certificates and wait staff has been cordial (you might remind wait staff that they are still getting tipped on the non-discounted amount if they seem grumpy about the certificate). You'd tip 15% anyway, and that extra 3% some restaurants reportedly add as "mandatory" typically doesn't add up to much - certainly not enough to whine and moan about publicly to one's own embarrassment. We've had a couple of last-minute changes of plans, and simply exchanged the certificate for something else.
That said, after getting a few certificates on special from, e.g., groupon, we haven't found opportunity to use them due to all the restrictions and most nearby participating restaurant options being a bit sketchy. I haven't yet found a way to get a refund, however.
In all, "meh" would be my review. When I've used the certificates I've saved at least 25% on the tab.