Borderlands wasn't that great an I don't think A:CM would have been ready 1st quarter 2010 anyway.
Gearbox isn't very good with game development (plus they do dumb things like rushing Borderlands out the door and so many glitches.) and besides A:CM won't even have an Alien campaign. It's no where near as valuable as AVP3 is.
The only thing A:CM has going for it is the 4 player co-op campaign, no HUD, and realistic motion tracker. but it won't be as replayable as AVP's multiplayer modes.