personally, ive never used cockpit view for a fight, even if it allows a bit of a faster turning, due to teh fact that i prefer to be seeing everything, my ship, my surroundings, enemy ships, and also, it doesnt restrict seeing if any more ships are coming, where as in cockpit view you can only view forwards.
as its been mentioned, everyone has their own preferences. some like cockpit view, some like ship view, some like turret view.
In dogfights, I think the ship view is better, because u can see who is beside u and the shots almost hiting u (u can try to evade) and makes u turn easier.
Cockpit view is good to aim with Gunboats or Cruisers (u can use Turret view too), and to pass trought asteroids fields with Trains, Transports or even Capital ships.
Ship view is best for fighting - anyone who says different is just weird and probably sports a 3rd nipple. Only known one top PvPer who claimed to use cockpit view & we all thought he was lying.
I try cockpit view now & again (for the realism etc), but the darn shake narks me & makes me cuss. It's hard to target in a fight with the blur of weapon fire obscuring the view & engine-kill manoeuvres are more difficult to judge.
Footnote
Its just a game pilots so fly whichever way you want & kill xeno