You might want to take advantage of this:
They have a great review system and it's quite easy to create a decent review.
Granted, after I wrote two reviews, it took two weeks a little gentle nagging for me to get my coupon, but they might well have been very busy right then. It's a new feature so I expect the review process will get quicker.
Their prices seem quite fair overall - the books I've looked up can compete with Amazon's European prices.