Pass through by far, especially if you use mechs. My dad hit his bear square through both lungs this year, but the arrow lodged in the off shoulder due to the quartering away shot. It was a perfect hit, but the arrow didnt go through the shoulder. In fact the arrow popped out when the bear ran and left the blades of his Rage 2 blade in the bone... Anyway we had a heck of a time tracking the bear through cutover because the entry wound was high and it wasn't bleeding up there. We were lucky to find it cause we could track it through the messed up leaves. It went about 100 yrds through thick cutover, I know with a pass threw we would have had easier time finding it.

Arrows dont have the same mechanics that a bullet has, in theroy you want the bullet to impart the most energy(read -damage-) it can on the animal through expansion, thats why we shoot soft point bullets to get nice expansion & create more damage. Since the expansion factor of a broadhead is fixed regardles a pass threw is nice to give you the bleeding. The old school thought is just that, old school, If it was the case that old school is always right why dont we hunt w/ spears? In the case where you dont have a pass through, most of the time the arrow would break off or get pushed back out, leaving you one hole and not doing a bit of damage...