Well I saw it the day after X-mas and I really liked it. It was sufficiently action-ey and there was plenty of kickassery on both sides. But personally, I think the single best thing they can do is set it in the same time as the games where the humans are actually viable enemies for the extra-terrestrials. The humans just plain sucked in AVP:R.
Well I think they just didn't want to have either one win because then fans of the other side would be up in arms. I know I personally felt a pang of hatred when the Pred got stabbed and I thought he would die. But then they both died and I was like "oh...well that's ok then."
Well it's like I said, if you ignore all the parts with humans in it you have a great action-ey gore-fest. The story is so-so but it's at least better than the first movie. The predator does NOT ally with a human, the Aliens are considerably more numerous, and it's rated R so it's considerably more gruesome. It was definitely a B-rate movie. Terrible by objective standards. But as a fan of the Predator movies and the AVP games I can say that my inner fanboy was satisfied.