My father has a Sotz Monster Maul. He's 76 now, still uses it occasionally. I asked him if he would give it up (I wanted it) he said no, so I bought a Bailey's "Mega-Maul", welded a 36" stainless steel handle on it and now I have my own. I like taking it on Boy Scout camping trips and having the Scouts use it to split firewood for the campfire.
I just noticed my 80 some year old neighbor has one too. If I can get around like he does when I'm that age I'll be tickled pink.
It's not as bad as one might think. Lift it up and let the shear mass do the work. I split that entire tree with it and while you definitely knew you were using it when you're done, it really does do most of the work for you.
I used both my Sotz knockoff and my True Temper "Total Control" 6 lb maul last weekend to split some ash. The monster maul was a "one swing, one split" deal, blew the 14-16" rounds in half in one shot every time. Swung that enough times, and then switched to the 6-lb maul, and I found my swing speed with the six-pounder had increased dramatically. All of a sudden you wonder where all that weight disappeared to. I did try out the monster on a piece of very twisted, wet and partially frozen poplar a couple weeks back. I could not touch it. Took a wedge and a lot of smacking with an 8-lb sledge to get through that poplar. I gave up at that point.