Movie novelizations are never what you would call brilliantly written, but then they never aspire to be. They exist simply to transfer the screenplay into book form, and maybe -- if we are lucky -- provide a bit more insight intro the story and characters. In that respect author Greg Cox has done a pretty good job.
The basic story is practically identical to the movie of course, as is the majority of the dialogue. But there is a lot more of what you might call "fan service" here. As we already knew, The Joker's whereabouts during the events of the movie are revealed (turns out he is Arkham's last prisoner..or, he's escaped) but the most famous of Batman's villains is brought up numerous times throughout the course of the novel, as several different characters -- Batman, Alfred, Gordon etc -- think back to his reign of terror over Gotham, and his terrible crimes, specifically the murder of Rachel Dawes. Selina Kyle is also referred to as Catwoman many times, and she even has claws! No whip, although one is mentioned. Really the only character we don't find out any more about is Bane unfortunately. In fact he's actually less developed here than he is in the movie. I was hoping we would get a bit more back-story, more info on the mask etc -- but then I guess that takes away the mystery, which works very well for the character.
Perhaps the most interesting aspect is how the book fills in a few of those "plot holes" that so many people seem to feel exist in the movie. The thing is, they just prove that in a lot of cases they aren't plot holes at all, merely a case of not having every little detail spelled out for you. Anyone who was paying proper attention to the movie could have filled in the exact gaps for themselves, without having to read them signposted in the novel. Of course this is possible mainly because in the book, we have the benefit of being allowed into the character's minds to get an insight into what they are thinking from situation to situation. Obviously that's not possible in the movie, but I think it's fair to make some assumptions! Anyway, read the book for yourself and you will see what I'm talking about.
The actual writing is merely..adequate. I mean as I said, you can't expect to have your mind blown with lyrical prose in one of these novelizations, but sometimes it does feel a bit too sloppy. There are moments of brilliance, but also some repetition, a bit to much exposition, and not quite enough descriptive power put into the more emotional parts. As a result anyone who has seen the movie won't get a whole lot out of it -- aside from the extras I mentioned. But at the same time I wouldn't suggest reading before you have seen it either, the movie is just so much more powerful.
In summing up, I would recommend this to anyone who wants to delve a bit deeper into the story, and find out more about the characters and their motivations. Otherwise, some great excerpts aside, I wouldn't rush out to buy it.