The Predators seemed keen, save for the fact that as compared to the ones in Predator and Predator 2 they took MAJOR steroids to look that buff. Especially since they were teenagers, by comparison. Upon Scar de-masking itself, the face was horrible! It lookd a little too humane as compared to the other Predators and I almost felt like he would've made out with Lex. That would've been an ultimate slap to the face to those that follow the Yautja closely. Also disappointed that the Celtic Predator got his ass kicked by the Grid Alien. He should've spent no time and just defeated the Kainde Amedha (Alien). I could've lived with the first Predator being dispatched so quickly, but two of them? That just made the movie shorter.
The humans were...well...laughable. I mean, sure that Predator had a couple of cheesy one-liners, but they made movie history. These were just pathetic. You couldn't feel bad about the people getting picked off left and right. I agree with a couple of critics in that Lex was no Ellen Riply. She tried too hard to be badass without earning it, but oh well.
Finally, the movie was too short. It wasn't enough Alien vs. Predator. It was everything else but that. The action scenes that actually involved battles between the two species were less than 15 minutes at most. An Alien wouldn't have attacked another creature with an Alien within it (see Alien: 3) and the pred-alien would've probably been crushed by an entire clan of Yautja onboard. I liked the movie, simply because it took that long to come out and because fans wanted it, but I wished they hadn't disgraced it as such. Here's to hoping they make a better version of it, or at least let someone else direct the sequel with a better script. Stick to the comics, they worked.