I believe two blades penetrate deeper, and shock less, but if you blow through deer with ease (Heavy draw weight and heavy arrow) i would go with a three blade just because of the much better blood trail. Hit a big buck a couple weeks ago, right on top of him at 10 yards, and hit him high, he stumbled like he was going down, but didn't, and ran out of my life. Penetration was poor, and no blood. I feel I must have short drawn my bow at the steep angle, and worrying about bow limb hitting treestand. I think had I been shooting a 2 blade this would have turned out different. Good points TJ, you got me to thinkin'......