I loved both Aliens vs predator games on PC, first AVP film was decent, the second one i thought was poor.
This is a good interpretation, the marine campaign is the best and is intense and creepy, fits in most of the staples of both francises, although it is way too short in my opinion. Firing a pulse rifle in blind panic down a dark corridor never gets old if you are of the generation that saw Aliens the first time round !
The Predator campaign is good as well, plays more like a stealth game, the alien campaign is the shortest and weakest but still worth playing. As a previous reviewer said the lack of a crouch button (especially in marine campaign) is really off putting as any experienced FPS player will reflexively expect it to be available.
All in all a if you're looking for an authentic "aliens" videogame experience this will do nicely ... i just wish the campaigns were a bit more substantial !