First person. The camera angle makes it tough for me to hit anything in third.
This, the camera angles can definitely screw things up, especially when in or near cover. Multiple times tonight I had people absolutely dead to rights but pumped all my shots into a railing or the edge of a wall strictly due to the camera.
Sometimes, the camera seemingly has nowhere to go if you're near an obstacle, and the character's body ends up completely blocking what I'm firing at from view.
This type of stuff doesn't happen much if at all in 1st person, but as others have said with the reduced field of view, i do feel like I'm at a slight disadvantage when in 1st. Decisions, decisions.