What's better Hawkbill or Reverse-S blade?

[Death's Head]

I just recently purchased a Spyderco Civilian and a Matriarch. The are both wonderful knives that have a lot of potential for self-defense. That is what these knives were specifically designed for. I know other hawkbill knives like the Spyderco Merlin and Harpy have thicker blades for more of a utility use and were not specifically made for self-defense.
My question is, are there any added benefits to the specific shape of the Civilian or Matriarch. It seems to you would defend yourself using the mostly the tip portion of the blade. The tip portion of both the Civilian/Matriarch and Merlin/Harpy are identical. So how does the portion of the blade closer to the handle benefit the holder of the knife.

 

[Axlis]

The belly of the large reverse-s on the civilian makes for killer slicing capability, which I WOULD NOT like to be on the recieving end of! A good reference for a ultility use of reverse-s in a small package is the Dodo, you have to hold/use it to understand the power

 

[Death's Head]

I need to get me one of those. That and the Yojimbo. Everyone always raves about them without any constructive criticisms whatsoever.