I prefer one that passes all the way through. Pneumothorax from two holes stops all breathing, particularly if you scramble both lungs, and the animal will only run a short distance. It's possible that bullets that don't exit may only destroy one lung. Heart shots with either work the same.
I agree right up to the point about heart shots... take out the pump and you remove both power and suction side so no blood moves. There is still a lot of available oxygen in blood after it gets run past the tissues... leaving it trapped in the meat lets critters run farther. Take the Aorta off the top and the suction side works and the vent dumps all the blood quickly.
