This is a discussion that i find interesting. I myself prefer First-person and i find that Dslyecxi have a really good video about it.
I do use third person quite a bit. I shoot while aiming down sight in first person, but the head bob on the first person camera annoys the shit out me, and makes me a little sick when moving around to much.
About the only time I use third person is when driving trucks, it's so boring I at least want a good view of the scenery