Agreed with the search being awkward. I tried searching "end of eternity" with and without quotes. In both cases, A Song of Ice and Fire as well as Fifty Shades of Gray came up [1]. I'm looking for a classic book by Isaac Asimov. For what it's worth, Amazon knows what I'm talking about immediately [2].
On top of the search algorithm being a little wonky, I think your sentiment analysis is a little off, as well. For example, for the book Caine's Law by Matthew Stover, you have the Two Pens and Kirkus reviews as negative, when in fact they were positive reviews.
I would love to see a site like this work--I'd be a constant user, but it's got some work to go before it's usable.