Pros & Cons of forward vs. counter-rotating tillers?
Forward turning can sometimes try to push a small tractor forward faster than you want to go - no problem; use lowest gear, even 4WD if necessary.
Counter-rotating tries to pull back on the tractor and
may require a little more tractor power to pull it.
When you reach the end of a row and pick up the tiller to turn, if you do not disengage the PTO, the counter-rotating tiller tends to throw more dirt forward and make a small mound just past where you stopped tilling - again not a problem that the operator cannot handle. Of course a forward turning one may make a little mound at the start of the row if you're not moving forward as you lower it into the ground.
If you encounter a solid object, buried big rock, root, etc., the forward turning tiller tines come down on top of it, the tiller bounces up in the air and rides over it - usually with no damage. The counter-rotating tiller tines are coming from under or behind the object and there seems to be a little more liklihood of breaking a tine or shear pin, or slipping a slip clutch.
Folks who know, or should know, more than I seem to think the counter-rotating tillers do a better job in fewer passes.
And the biggest difference - price! I've never understood why a counter-rotating tiller should cost so much more than a forward turning one. Maybe someone else can explain that.