Used it lots - got my money back (£5 for 4 or 5 yeras I think) first time I used it. Up to 30% off meals in some pretty good high street chains, 10% seems about average - Halfords, Clinton Cards, Burtons, Go Outdoors, Hackett - the list goes on.
KFC, Subway, Garfunkels, Harry Ramsden, Hotel Chocolate ..........
So why not? If I take the grandteeters out to eat, and someone - usually Frankie and Benny's - want to knock a fiver off the bill - who I am to argue.