Found this useful website totally by accident, Pissed Consumer, because it had some postings about Michaels Arts and Crafts. My disclaimer: I've can't remember a bad shopping experience at Michaels.
Pissed Consumer has a pretty interesting blog as well. Lesson to learn here for your arts and crafts business? While most customers are too busy to write great reviews, most will take the time to pass along their bad experiences in great detail. I especially like their "Free cheese is only in a mousetrap" analogy when discussing promotional deals.