I wouldn't go for the head under most circumstances. Stuff can change really fast. I headshot a bear by accident once while going for the double lung. He swung his head around while I squeezed the trigger. It's a good example of how much movement can happen so quickly.
I did go for a neck shot on one occasion, but only because the bear was sleeping and the chest was behind a tree. I lay there prone for 45 mins with it in the cross hairs before my brain told my finger to squeeze. It all worked out.
If you are somehow certain an animal won't move its head and you're 100% confident with the shot, can't argue with that though.