I used to have one- wasn't that impressed with it to be honest. The edge geometry was just all messed up for any kinda wood cutting- way too thick. I'm sure it would be an awesome fighter, but for wood, I'd get something else. hatchet, khuk, or just a big knife.
One could make a point of the ATC's lightweight, but I had even lighter hatchets equal it, and barely heavier ones bury it. ie: short handled Gerber Pack axe. I won't even get into the difference between the ATC VTAC and my medium sized $20 Fiskars garden hatchet...
As far as wood thickness, any prolonged cutting of wood much thicker than a 2x2 would probably make you a tired man quickly.
If you primarily want a weapon, I'm sure the VTAC would be awesome, if you want a tool however, you might look around a little more at whats out there.
Edited to add: you might want to also check out the hawks at hbforge.com and ragweedforge.com Been eyeballing the Nessmuk at Ragweed myself.
