Finally got around to it.
First impression on performance is that DX11 executable (even on non DX11 hardware) is noticeably faster than DX9.
First problem on performance is that 10.1 ATi drivers and later sends me to desktop when I load a save.
First solution on performance is to use 9.2(note 9.2 hotfix version gives about 5-10 FPS more on the high end, keeping you nice and smooth). 9.2 vanilla is a bit slower and stutters some.
First impression on visuals is that it DOES look a bit outdated, I was expecting a bit more, but unfortunately..consulitis was not avoided here. The built-in AA does an ok job, but some areas it's really noticeably lacking.
First impression on gameplay is that when playing Marine, the weapons are awfully weak. In close quarters versus multiple aliens, you're pretty much screwed unless you grenade launcher them. Even the "normal" setting is more difficult than it would be in other games.
Predator controls are good, and neat as well, though that whole 'hold mouse 2' > 'mouse 1' to stun an attacker gets a bit annoying. Really it should just say Block>Light Attack. I'm also surprised how weak the Predator is, he dies way too easily.
Not done Alien yet, will get to that soon.
First impression on audio is that they're very well done, although a bit watered down. They could be a bit louder and more surround oriented.
First problem with audio is that now and again you get a speaker popping and intermittent cutting out of sounds.
First solution with audio has been none, except to not play any of the audio tapes you pick-up; though might be placebo.
First impression on stability is not so great. I get crashes everytime at particular locations, and it's really annoying that when you save, it doesn't save where YOU saved, it puts you back at a checkpoint.
Multiplayer as already discussed, but Co-op is where it's at. I cannot really get into any deathmatch, because Predator tends to end up being a one-shot 1:1 kill to death ratio frag fest.
If I could just get it to stop crashing, I'd be content.