I'd rate this film higher but for a crucial element of the character that was entirely absent - charm.
Having read a fair amount of literature from respected criminologists and criminal psychiatrists (which confusingly holds that psychopathy might be linked to a disconnect/dysfunction in the amygdala as frequently as it cites environmental influences) the one thing they all agree on is that high-functioning psychopaths are often charming, engaging and highly intelligent.
Yet Bateman's character is as smug and charmless as can be imagined, to the point of cartoonishness. The film therefore misses out on the one element that would introduce a genuinely spine-tingling response; that the charming, friendly, talkative, interesting and apparently helpful man smiling at you across the table is mentally visualising how best to dismember you once he gets you home.
Given that Silence of the Lambs preceded this film by a wide margin and showed us how a real pure psychopath would behave there really is no excuse. To be fair, they got his profession right: alongside Politics, Law-enforcement and Special Forces, the density of psychopaths in the financial sector is much higher than anywhere else in society. (This is not a criticism, just a fact that positions of power/control/authority is naturally where psychopaths congregate).
It wouldn't have been rocket science to portray Bateman correctly and hint at his darkness in separate, less pleasant, vignettes. Unfortunately the Bateman we see is aggressively psychotic in broad daylight and to anyone who sits "below" him on the socio-economic scale. His lack of interaction with any kind of employer to whom he must show at least a modicum of manners skips the chance to demonstrate the truly self-serving and ruthless nature of this kind of creature. In the wild, such a man would not remain undetected and at liberty for long.
The film is entertaining enough I suppose on a frenzied-bout-of-violence level but to anyone who has done a bit of reading on the topic it's mostly two-dimensional and barely believable.