I'm gonna copy/paste my response from another forum...

I'm at the Maersk Alabama rescue and so far the campaign has been rather meh. Having to restart the mission multiple times because the game stops recognizing my keyboard (until I hit escape for the menu) is annoying. The story is meh. The cutscenes with the family definitely fall far into the uncanny valley.

I actually enjoyed BF3's campaign. And thus far, it's been the better experience for me.

Multiplayer is pretty good. Been having some serious high ping issues related to my ISP, so I haven't been enjoying it as much as I could. I enjoy the workbench style customizing screen for the weapons. I wish the game would tell you what weapons you've unlocked accessories for, though. Otherwise it's going from class to class, nation to nation and gun to gun trying to find out what the numbers on the menu are for.

And VOIP needs to be able to PTT, damnit!
How is the unlock system and is there a hardcore mode? If so what does it do?
Rather convoluted, I think. You have 6 classes. And then you have something like 15 nations per class. Each have their own variations of weapons. I'm not certain on how you unlock stuff for it. Might be kill based, but I can't really tell.