I watched it opening night, went in with high expectations and left feeling..meh. I did not hate it, i got some enjoyment out of it. I would say i'm very indifferent about it. It's obvious that Anderson wanted to make an "Alien" movie, he said so in all the interviews, it seems that somewhere down the line he got roped into adding Predators.
I love both creatures but it's obvious that the aliens were favored. I liked AVPR a lot more, still not an award winner but better in my opinion. Though one could argue that the Predator is favored more in that one. I think that's the problem with versus films in general. Two great characters that can never be balanced out in a way that will make fans on both sides happy. Freddy vs Jason..same issue.