Ya I dunno how you guys are having issues. I have a pretty old comp, duocore 2.16ghz or something and a 4650. Running perfect on near max settings.
Anyways the game is a total blast. I just hope we get new maps soon. The variety of weaponry is awesome. My current fave is Jaeger + vindicator + telsa gun + freeze grenades. Vindicator one shots the basic common alien and does ****tons of damage to everything else, those inciendary nades are great too against the big aliens...and the telsa gun is great for when you're getting swarmed and dont wanna team dammage. Plus it's nearly impossible to run out of ammo on the telsa (good back up). Actually I think the telsa gun is a bit TOO good, and needs to be nerfed, not sure how though.
And the freeze grenades, again, are good when you're getting swarmed, or against a bunch of the giant aliens.