A book that seems more concerned with trying to convey an idea than actually tell a story. 
 This is a world in which humans shy away from knowledge and seek purely to fulfill basic pleasures in various forms of entertainment, mostly via a form of television. People try to fill every waking moment with inane entertainment in order to avoid having to think. This is a world where this kind of behavior is accepted and valued by the majority of the population rather than being forced upon them (a dystopia more akin to Brave New World than a 1984). 
 The book is, ultimately, a theoretical discussion between those trying to justify living in a world that shuns books and knowledge (the majority) and those who think books and knowledge need to exist (the minority). These ideas are discussed in depth and and are interesting and insightful at times. But therein lies the problem. The book sacrifices everything in order to convey this one argument to the point where the characters feel like abstract concepts rather than living humans. 
 Most of the ideas are conveyed through extended monologues which are cumbersome and heavily impact the believability of the characters to the point where they simply become a mouthpiece for the ideas the author wants to express. They have no identifiable mannerisms, no defining characteristics, no voice of their own, no real backstory - simply, they have no depth. 
 When Bradbury isn't discussing his main thesis, rather than spending his free time fleshing out his characters, he instead invests his energy in describing things with flowery prose. I generally like flowery prose (he does have some nice descriptions) but when I don't really care about the people and thus the world they inhabit then the descriptions become a bore, they lose their impact. If you want to write flowery prose then you have to earn that right by making me care about the things (the world) you're describing. 
 I agree with the sentiment and the story's moral. Books are important. Knowledge is important. But just because Bradbury's message is a good one doesn't mean the story is well written.