I got in the beta and have been playing it a bit. Pretty impressed so far.
I don't think I have ever played a game that so accurately reproduces the feeling of actually being in combat. I don't know if just thanks to the amazing motion blur and DOF effects they use. But it just really feels authentic and not game like. For me, the feelings I get when in this game are more like the feelings I get when watching Black Hawk down or Saving Pvt Ryan than say playing R2 or COD.
I don't think I need to harp on how good the graphics are. It has been posted and repeated so many times. I think people shouting it even more might start to backfire on this game. But it hard not to...
I like the sizes of the characters, I like the movements speeds. I like how the characters feel like they have real weight to them and are shifting their bodies around not just floating around the floor. I love the jump mechanism in this game. It is useful while at the same time prevents stupid stuff like bunny hopping because you can't shoot when you jump. Plus the jump animation the reload animation is perfection.
So far what I don't like or what needs to be improved the most is the audio. The individual sounds themselves are fine. But there seems to be some bugs when dozens of different sounds from mutiple directions are being mixed together. I feel like it is not accurately reproducing the sound scape. Maybe because the graphics are so good the audio has a hard time matching it.
There are some other little niggles that have to do with the multilayer code not the basic mechanics. And some weird physics with dead bodies that needs to be fixed.