Another option which I like better than gut reactions and before I buy books is to go to the library or the book store and try to read some of it there.
I regret that the word I hear is that BOARDERS might be about to go out of business (is in financial difficulties and losing to Barnes and Noble and Amizon on book sales) as I find it the best place to go peruse their books and have a snack too. Seems to me they are more accomadating in terms of seats and tables for this than Barnes and Noble. But, Barnes and Noble is good too to go spend hours or most of a day reading their books.
I do this a lot and I probably buy only about 1 in 20 (or 5%) of the books I start reading and like. I rarely take the time to finish the book there in one sitting and put it back on shelf, but I have done that a couple times too. My 5% purchases might approach $1,000 a year (more or less) in books and magazines. Nobody at any store ever has said anything to me like "are you just going to read or are you going to buy?". I also go to Books a Million (only because it is closest) and think they are the least accomodating in the seating they offer, but they do have tables and chairs in their snack area (and a few comfy chairs) and you can read there for hours too.
At Boarders, you can also listen to ANY CD they have in stock and buy it or have them rewrap it and put it back on shelf! Very nice when you only know one song you like on a CD and don't know if you will like or hate the rest ... and unusure if you want to pay the price of a cd for one song you like.