I started out with Muzzy chisel points. That was the best solution back then before I figured out how to sharpen a broadhead correctly. Now that I know how to get them shaving sharp, I've gone to Zwickey then Woodsmen Elites. It makes sense to me that cut on contact heads probably penetrate a little better than chisel points; but I'm not convinced the improvement is really all that significant. As many have said, how far in the dirt do you want to bury your arrow after a passthrough..
I've used mechanicals for turkeys a few times, but they failed more than they worked for me. In my opinion, mechanical broadheads have no place in bowhunting; period.