Sorry about the confusion about reversing. I use my tiller at times when I'm digging footings and such with the loader. When I'm in clay I will open the soor and run the tiller while backing up. It digs in better to loosen the ground. It chunks it out though and I wouldn't recommend it for finish tilling. As far as I know except for some hand tillers they don't reverse the rotation. If a tiller did that I would imagine that the blades would have to have cutting edges and angles on both front and back edges.
You are certainly right on about tillers taking a beating. I acn't tell you how many times a person has told me that "oh there's nothing in there" before I start chewing and have the tiller bounce out of the ground on concrete, steel, and the worst, steel cable winding up in the tines. I will say that I have broken tines, bent them and the flanges on the rotor axle, but never did take out a set of gears. I do prefer them over the chain final drive. Remember, this is just a personal opinion, and I'm sure that others have some reguarding their blessings of other systems.