Just wonder if the publisher could arrange to get rights to it's books' reviews across seller sites and aggregate the results. The truth is, apart from occasional sales like this, the publisher sites are rarely in price competition with any other sellers.
But as far as Amazon goes, I'll buy the books in paper (or pay more for DRM-free) to avoid the Kindle DRM and being locked into one ecosystem. It almost feels like a luxury to be able to loan out or give away paper books. Kindle books just feel more like renting a book than owning it. Which is, legally, probably a closer metaphor for the transaction.