Ok - I'll chime in. I think, dramatically, AVP is a total piece of garbage and Paul Anderson needs to stick to making films based on video games. The guy seems to have a handle on the look of these characters and their environments, but looses the threat of them in the translation. The Aliens were unstoppable (nearly), blind killing machines with no emotional response. I think this was perfectly captured by Ridley Scott in the first film, and to a lesser extent, Cameron and Jeunet. You could not reason with them - they were purely instinctual.
The Predator, conversely, was conniving and tricky - it planned its kills perfectly. However, at the same time, it wanted a challenge. In AVP, it was clear that the Preds outmatched the Aliens. The Aliens were reduced to growling animals and, despite their agility, seemed far to soft. The Preds were reduced to hulking juggernauts, without any of the samurai-cool evident in the first films.
That said, the CG work in AVP is most impressive. I literally got a chill seeking the Alien Queen on a full-on sprint out in the snow. Also, the design elements of the Predator armour was pretty sweet.
Just my thoughts.
Scott