The Alien campaign in AvP is fun, but the marine campaign is a boring disaster full of instan-kills and doom3 style monsters jumping out of obvious locations. The multiplayer is fun, but if you want to try it I suggest the PC version. I had it for consoles, and the console versions support was dropped like the same week the DLC came out. The PC version got a much needed final title update. The multiplayer in it is good fun on PC and I still log on from time to time. It can be a lot of fun at times.
*The Cadillac of signatures*