I think their weapon system is overly complex but much easier to understand in comparison to BF3. It's clear this is far more of an arcade quick blast type game than BF3.
Loved the 'feel' of the guns - you could some how tell they felt good just as in previous MW games. That was the beauty of CSS actually, the way the weapons handled.
So far, I've only played about an hour's worth of BF3 (single player campaign) and the weapons don't do it for me at all thus far. Nor does the game actually but then it's not surprising. It feels like more of a rushed or half hearted and not-completely-committed attempt to distill the epic MW moments and it's not there by a far margin.
Graphics are pretty good though, especially the enemy player models and their animation. Not sure about the general environment though - don't like it too much graphically. And it's weird you can't shoot lights out. What's with the dynamic lighting system, eh, DICE? Well, not to worry. The multiplayer experience ought to be a little better.