For a film that is centred around murder and sexual violence, it's surprisingly engaging to watch. Whilst Bale plays his most dislikeable character, this is one of his most stand-out performances. It is full of shock and intrigue, and although it feels a lot older than it actually is, it has a great and somewhat classic feel to it. I hear the film is not half as gorey as the book but there's certainly enough here to make you wince.
Aside from the superb acting and script, a strong factor of the film is the use of Bale's character's narration and monologues, focusing on the irrelevance of his every day life, from his shampoo to what font he uses on his business card, which is then contrasted against his brutal actions. What I like most about the film, however, is that each time I have watched it I have understood a different conclusion - the first being that Bateman was so bored with his mundane life that he made everything up in his head throughout the day - the way he tells people he likes killing people and they don't catch on - and the second being that he did kill all of these people, but that nobody believed him because Bateman was too gutless and/or they just didn't care about anything going on around them. Whilst this leaves you feeling a little confused at the end of the film, I feel that this is one of the film's best qualities. Of course, that might not be able to be said for the book, but I still think it would be very interesting to read.