I just watched it for the 3rd time. David is the centerpiece. He is a multi-faceted villain. The other characters are okay, but mostly boring. The neomorph design is cool. The creature CGI was spotty. The xenos were brutal, but die quickly. Not a bad film, but it suffers from dumb characters.
One thing that has kind of nagged at me since last night was that it just somehow feels a bit hollow as a film. I can't put my finger on it (and no I'm not hung up on the origin thing even if it isn't my first choice). It just seems there was a lot of dead air surrounding it.