Please consider this as merely some things to consider.
The wood I am most likely to split where I do my camping/backpacking is hardwood.
When it comes to splitting hardwood, an abrupt shoulder where the blade meets the cheek of the head (less like a ">" and more like a "T" when viewed from top of tool) results in the need to exert more force to split the wood.
The Vaughn mentioned, the Norlunds, and many American-made axes have little or no shoulder. (The Vaughn I bought came with the head cocked on the handle and a horrible edge. :barf: )
I have three GB's: Wildlife; Hunters; Small Forest). They cut like the devil. Great for felling, bucking, and limbing. They are relatively poor hardwood splitters due to the presence of a pronounced shoulder.
I have a Wetterlings Wildlife. It is better than the GB's at hardwood splitting. Less shoulder. Not as well finished as the GB's but seems to cut just fine. Less expensive.
I have several hawks. The Ft. Meigs (or is it Miegs? Ragnar doesn't seem to carry them anymore.) being the only exception, they are relatively poor splitters.
I have three Estwings. They have a concave wedge top profile. They split well but should not be twisted in the cut to speed splitting. (I have used them less and less because they lack the ability to comfortably "choke up" for fine work and are fairly soft as compared to any of the axes/hawks mentioned above. Can't imagine breaking one.)