That's an excellent question. What is the advantages one over the other?
I would imagine the reverse tine rotation would use more power to operate since its going against the direction you're traveling, using more fuel. But If you're making more passes on the forward rotation tiller that will use fuel too...
I could see where a forward rotation would be better with rocks, because it would climb right over it.
Here's something I was told by a landscaper, "Reverse rotation tillers are excellent for prepping a new lawn, because they burry all the stones." Don't ask me how or why. Next time I run into him I'll ask.
Gary, you said having a tiller that you could change the rotation around like the Tarter or Howse is too much work, I highly doubt you'll be doing it more than twice. I bet one will be better than the other. I just don't know which one that is. That's why I'm leaning towards one that you can go either way.