I will try and get a broadside, either heart/lung or high shoulder shot if at all possible. If that shot does not present itself and I don't feel it will, then a neck shot is not out of the question. But as has been stated, although a good neck shot usually leaves the animal DRT, the 'bulls eye' or (as Pahoo put it) the 'kill zone' is much smaller with the neck shot compared to the heart/lung shot.
I know my rifle and my capabilities/limits with it. Too, I stay within those parameter's and would much rather let an animal walk then risk causing it to suffer. Many of us here know that horrible feeling.
The reason explained above is the reason I will not do head shots.