I don't have a dispute with Cliff's remarks but would like to add a couple observations. First, you also need to look at the design of the specific hawk when comparing it with a hatchet. For example, go to
www.2hawks.net and
www.hbforge.com and look at the different shapes. Two Hawks' Longhunter has an entirely different head shape (for chopping and other general uses) than his fighting/throwing hawks. The cutting edge is somewhat smaller, the head is heavier, and the edge is angled to match the arc of a chopping stroke. There may also be differences in edge grind, but you'd have to ask him that one. In any event, it bites really deeply on impact.
I have been meaning to carefully compare the Longhunter with one of my Gransfors hatchets (like the Wildlife model) but have not yet had a full opportunity (presently living in the city). However, based on my limited experience, I found that the longer handle of the Longhunter allowed a somewhat harder strike. However, the straight grip was not as ergonomic as on the curved Gransfors handle, and the hawk shaft transmitted a little more shock when chopping hardwood. I wrapped about six inches of the hawk shaft with paracord and will be interested to see how that addresses the grip/shock issues.
One other advantage I noticed in the hawk was that the straight shaft makes it a lot easier for me to do light cutting in a "choked up" grip. On the Gransfors Wildlife Hatchet, the curved handle was a bit limiting for me.
I'm sorry that I can't give you a final opinion one way or the other at this point, but it is certainly a lot of fun experimenting with these different implements.