Having played the game, I can say its "good". But its a bog standard FPS. Graphics are impressive because they are consistant, but up close they aren't as good as Sony may have you think...
Still, its a good game. Just doesnt raise the bar at all for gameplay.
The PS3 does need some good games. Bring on Uncharted 2 I say....
EDIT: Thought I should mention I played the review build, not the beta.
I played KZ 2 quite a while ago when I was at their studio.
KZ 2 looks good, the AI is decent in SP and I managed to own in some MP LAN battles. It's a decent game with some fairly intense fights but - at the time I played it - the SP pacing was really bad. Almost monotonous.
I'm assuming since then they've addressed those issues. I'm also hoping the team didn't burn out to finish this game.
The demo was awesome. Got owned after running into the action blindly. Next approach was done more carefully, seeking good positions and taking a lot of cover. The AI is quite nice so far. They smoke you out with grenades and take in tactical positions.