RE: carbon vs other material
I have a friend who once shot a bear with an aluminum arrow. The bear spun when it heard the release and a double lung broadside shot at the release turned into a 'Texas heart shot' by the time the arrow got there. As near as he could tell, the arrow got bound up inside the pelvic arch and the first 3" broke off. The broadhead continued on thru the guts and diaphragm, taking out the heart. But he was shaking in his boots because he saw almost all the arrow sticking out the bear's butt, and he was on the ground, not 30 yards away from a jaws poppin, angry bear.
Well the bear dropped dead a few seconds later, so my friend didn't get et up. But the moral of the story is Stuff Happens. Would a different arrow, ACC or otherwise, not have broken? Would you have found your bear if you'd been shooting a different arrow? Who knows.
I have to say if I could afford them, I'd shoot nothing but ACC's. But I'm not going to say they'd have really done any better in the situation you described.