Amazon’s user reviews for books are problematic because they serve more than one master. They’re meant to help inform consumers, sure, but they’re also meant to drive sales, and sometimes they’re even used by angry consumers as a form of protest. If you’re looking for more honest feedback on books, try Goodreads.
Goodreads is a free community site for readers that lets anyone rate and review books. The big difference between Goodreads and stores like Amazon or Barnes & Noble is there’s no direct commerce involved, so reviewers aren’t writing comments with an eye toward persuading another shopper one way or another. For the most part, Goodreads reviewers don’t care if you buy or borrow or ignore the book, because they’re just enjoying reading and sharing their thoughts.