I don't think they themselves are happy about it.. the other kindles are doing a lot better review-wise. But the demand is huge (if you ordered a kindle upon its release in Germany, it'll say that it'll ship in January), the tech is new (and is going to improve) and apparently many customers are content. Nevertheless, all the returns can't be that great, neither from a customer relations PoV nor from a business one.
Anyways, I know that if I do get a bad one, I can return it and receive a new one within a couple of days. Even if the rate of bad units is too high, amazon's customer service is awesome.