I only read the book, which at the time I thought was a very good read, well executed and at first I had a hard time because I loathed Bateman so much. He has so many qualities I hate, aside from being a "supposed"* killer. I reconciled with a friend later on and he told me my feelings were normal. I later began to feel an almost pity for him and how his life was materialism incarnate and his attempts to behave normally toward his wife/girlfriend never go well.
I say supposed killer because a very interesting possibility for the movie and book is that Bateman never murdered anyone and was in fact insane/schizo. This made me like the book even more.
Don't really think Bateman is very funny, just a perfect as*hole. I never did watch the movie but I think frustrated males like him and his buddies because of their overboard misogyny, which kinda bothers me but hey to each his own. I admit, I'm a sensitive person, others aren't. The book is intense, I can't decide if American Psycho or The Painted Bird are more graphic. TPB is just downright cruel.