Finger, My OWN personal experience is that the hex and Hammer(type) have cupped faces with sharper edges that tend to catch more material and stop the head quicker in dense material like a stump or even mud. The standard blunt... not so much. They deflect and zing under and around.
I also find ( again, my own experience) that the wider heads, although they may grab more than the Hex heads, they also have this aggravating tendency to catch hard stuff, like rocks, posts, hard trees, etc on one of their edges, which ( again.. for me) results in enough side torque to break the arrow right behind the head, losing the head to the woods.
I use hex heads or, for skwerls, I make and use nutters, which is cheaper, works OK and, well, it is something I make instead of buy.
ChuckC