I had a similar offer, and the response was outstanding. Based on data I've been able to gather and analyze, people here are thoughtful, avid readers. I initially posted to gauge interest, thinking anyone and everyone would just snap it up. In a 36 hour span in which I put up a promotion, I had over 670 unique page views, yet only 282 sales. Knowing that people have varied likes and dislikes, I was thrilled that people took the time, read a bit, then decided to either use the coupon or decline. Shows me that these readers are looking for works that suit their tastes.
Good luck with your promotion!