I have killed a half dozen Deer with a neck shot and they all dropped right where they stood. As for the ethical part several factors come into play. Distance is a big one, I use the neck shot for relatively short shots, under 100 yards. A firearm that is capable of precise bullet placement with a good hunting bullet. A good steady rest with total confidence in my ability to make the shot.
I aim for the center anywhere on the neck, I think it is a fairly big target and an easy shot to make when one has the right circumstances.
Al