My neighbor in Oregon had a Howard walk behind and I second Mith, it was a serious rig that could do some real work. I helped him convert the ignition over to chevy electrics so he could keep it running on the cheap and that baby sure could chop clay were other models would just dance on the surface.
That said, farmers around here in rocky soil New England say
"You never want to buy a used rototiller" and with all the rocks that I have sent into the woods with my bush hog (which I bought used and have spent some time on with the welder, torch and grinder) there is something to the saying. It doesn't shave granite very well. BUt then again, a new bush hog would be just as beat up after a run around the feilds but for 5x the $$$
My wife is a fan of raised bed gardening so I am off the roto till kick for now