I do the ATV with a trailer method for my firewood. Usually I can get the trailer right to the tree and then buck up the firewood then, sometimes I even split it in the woods, especially if I can't lift the round... I can haul around 1/5 to 1/4 cord at a time and drive up to my pile and stack it. I have borrowed my neighbors arch and hauled out 1400lb saw logs with it but for a bunch of 8-10" diameter firewood logs the arch is a pain to use.I don't know if a small tractor skidding would have more production or not, depends mostly if you have to play around using cables to get the tree to the trail or not and the size of the trees. Also with an ATV I don't worry about getting stuck too much, I can move either end and there's the winch on the front so it not hard to get unstuck. Also sidehills aren't too scary with the ATV.=I use an old 300 kingquad which seems to like heavy work so far, its got more gears (3 ranges, 5 gears + reverse)than many old tractors and a front dif lock which helps when backing the trailer up steep hills. They are going pretty cheap compared to the new stuff and most guys who bought them aren't into abusing stuff.
Ian