Your complaint is a little non-specific, but I can add my problems with it here.
The biggest problem is that I get stuck to cover a lot. Ctrl is the vault button, but using space to leave cover also vaults you over the cover so I can't use space to get out of cover. Using wasd to pull away from cover usually just pulls you around the corner a few times. I've heard disabling vaulting while sprinting makes it so space doesn't just vault you over cover whenever you try to leave cover, but that is a really harsh trade-off. I like being able to vault while sprinting. I don't understand why they are connected.
I also often have the problem where I try to strafe behind the cover and instead the game stands me up and I get killed in three shots by some wannabee ganster holding his smg wrong.
The whole thing just feels clunky and very much like an unpolished console port.