If you know you need that level of chopping 'power', then the ~19" class of axes is really handy. If you only do light chopping, or know you'll have plenty of dead wood for fires/shelter where you camp, then they can be overkill in a hurry.
I've got a couple of GB's (no SFA) anda 19" wetterlings. There is a large gap in fit & finish between the Wetterlings and GBs, but the Wetterlings is still a great tool IMO. Works well and chops smoothly.
I've also got a ~17" Brian Andrews-modified S&N 'kindling' axe, and it's a real winner. Superb grind, nice broad cutting edge, smooth face. It does a lot of work in a small package. That said, if I could do it over, I'd go for the longer 24" camp axe (or whatever it's called). The equal head would be put to much better use with a few more inches. The advantage of the kindling size is it will fit in a rucksack though.
The S&N is a great value, and Brian performs some great modifications that really improve function for a very modest price. If you go with S&N, I can't think of a reason to not get one mod'd by him. Versus a Wetterlings, it's a tough call. The S&N chops better for me, but the Wetterlings is more comfortable to use due to the extra length. It also weighs less than the S&N. The GB's are made for softwoods, so that may paint your perspective a bit as well.
All three are great tools that will serve you well. Try
www.bensbackwoods.com if you go with the Wetterlings/GB. Go with Brian's mod if you go with S&N.