The official novelization of The Dark Knight Rises is the best film novelization I've ever read. Yes, I know that's not saying much, but the book is most certainly accurate.
To be sure, the novel follows the script - scene for scene - with lines of dialogue and descriptions clearly based on the shooting draft of the film's screenplay.
The necessary prose that fits between these lines is surprisingly good. Remember, such novelizations are typically a phoned-in affair, rushed at every stage, and put out to the public only because they know the book sell at least a little no matter how bad it is.
This obviously isn't the case with The Dark Knight Rises. There are no basic narrative flaws, and no typos. Each scene offers a well-chosen point-of-view character - rather than an omniscient third person narrator for the whole book, like most film novelizations - and the internal thoughts of those characters are consistent and uninterrupted.
These points of view provide us with quite a number of interesting details that we don't see in the film, as we can't obviously can't peer inside the heads of characters.
The best example is mid-way through the book when Selina is considering her trip through the halls of the prison that Dent's law built, and she thinks about the fact that there is only a single prisoner still left in the Arkham Asylum across town: The Joker.
This is a major revelation, and explains why Joker was not freed with the rest of Gotham's prison population in the film ( a question I had, personally).
We also come across general canon revelations, especially from the scenes in Alfred's point of view, in which he's frequently musing, in his head, about Bruce's childhood and Bruce's parents, while interacting with his boss.
In addition, since Cox was writing from the shooting script, not the final cut of the film, the book includes several scenes that were later cut from the film. True, they aren't major revelations, and we will also get to see them on the Blu-ray, but it's probably still worth mentioning.
Nevertheless, the book is still a novelization, rather than an original story. Meaning, it's not better than the film and probably not the best way to enjoy the story.
Overall, The Dark Knight Rises novelization is a fun, and somewhat time-consuming way to enjoy the plot of the film at your own pace, letting the reader consider each scene at leisure without getting distracted by special effects. It's well-crafted, and offers up a lot of great information which is not present in the film. I wouldn't pick this one up as a stand-alone, but if you loved the film, and want to get more of the canon story, this is the way to do it.