I made a video of this a while ago ->
But to type some things out here as well.
GOOD:
* Animation SMoothness
* Inventory management
* Inventory Space and body, armor, Backpack system
* Weapon Customization
* Vehicle Mirrors + back-side Camera
* First Person In vehicle as gunner
* Physics is a great improvement, not just to tweek it
BAD
* Bad FPS while in a multiplayer server
* Game Crash on random times
There is actually a ton of things one person can name that is good or bad. But it still remains the best fps game that brings out your true skills in realism. GOTY 2013 IMO!