during the movie, you'll find out that you'll be hating on both aliens and the humans--sometimes it flip flops.
You'll be able to relate to the main character. This relation doesn't come from his background, but really it's the way he reacts to situations and the way he solves his problems. He's scared, but also human, and I felt like the movie did a pretty good job of highlighting this aspect of his character. Although, I did feel like they smothered the audience with these qualities, but it's entirely bearable and, really, not that noticeable once you're out of the theater and you do a post-movie reflection.
The aliens, I wasn't sure how to feel about. First, you kind of feel bad for them because of how they were found. Then you kind of hate them for a while. Once Wikus runs off into District 9, though, you really get an intimate look at the aliens. This is where you really get a taste of their character, and form some sort of sympathy for them.
The action was pretty fuckin bomb, also.
long story short: Movie was dope. Go see it.