To be a little more constructive than in my previous post:
I did think the novel picked up considerably once Aliens were actually running amok, and I even quite enjoyed the interplay between the hero group and their adversaries in the midst of an Alien outbreak, but none of this happened until really late in the game and then the book just kind of ended with no real climax. It's by no means the worst Alien novel I've ever read - I'm not sure anything about it was even especially bad - but it was thoroughly by-the-numbers and middle-of-the-road.
It felt every bit the media tie-in it was. Has there even been a good video game tie-in book?