There's an inherent problem with making a movie of this kind: unless you're a creative genius of your time, these sorts of movies have the potential to turn real generic, REAL fast.
Reminiscent of Denzel Washington from Training Day, we see Samuel L. Jackson play an overly aggressive cop with an agenda, with the movie focusing on the problems he's causing for his new neighbors. A completely realistic situation that can take place anywhere. Problem is, because a movie like this is completely character driven, after you have the nice slow build up to the climax, once the tension snaps, you're relegated to basically a generically default final act of the movie where "the bad guy finally comes out of the proverbial shadows and literally chases the hero." (i.e. Disturbia, The Glass House). It's a shame too because the buildup on this was very good. Samuel L. Jackson was really scary here, he played that bullying, obsessive character perfect. The only acting problems I saw were 2-3 moments from Kerry Washington where her sad face was done poorly, with overly done lip quivers and facial movements (similar to Kirsten Dunst's crying scenes from the Spider-Man movies, except done in a BAD way).
With a movie like this, you pretty much have these possible outcomes:
1) the generic, semi-predictable ending (like we got here).
2) tragic ending with hero dying at the end.
3) an unpredictable twist coming out of left field (this has the potential to be very good or very bad).
4) a Great ending.
Unfortunately we usually get number one, since they wanna give the satisfying, safe, effective, tried and true, Hollywood ending. Most people are content with those types of cop out endings. I'm not.