City of God is the better film here.
The City of God cast lived in the favelas that the fictional characters and gangs occupied which brought a grand sense of realism and in some cases almost a nonchalant air to the subjects being touched on. Neo will be forever considered a hero, but as a character he didn't really do a whole hell of a lot. He was faced with change and eventually embraced it. City of God just has a whole cast filled with engaging characters although one could argue that the narrator, Rocket, is perhaps one of the more boring ones.
Knockout Ned and Little Zé are almost hypnotic to behold whenever they are onscreen and the clash between the 2 sides they operate at the finalé captures the chaos extremely well.