The owner of popular London coffee house Prufrock Coffee (and the current World Barista Champion), Gwilym Davies, has come up with what I consider one of the best retail marketing programs I have seen for a while.
He calls it his disloyalty card. the objective is to have his customers taste the coffee in 8 different, high quality establishments in the area, getting the card stamped at each. Once the card is full, he will give you a free cup of coffee.
Lot's of things here, obviously this states pretty clearly the confidence in the product. Perhaps more importantly though is the element of breaking the mould that most loyalty programs have conditioned consumers to tune out (do you have a Nectar card?..)