I use a single shank King Kutter behind my little New Holland. Like Brian said, they really do work. Before I had my tiller I used one on my garden and then tried to till it with my Troy-bilt walk behind. It had broken the ground up so much and made it so rough that it was almost impossible. At that time I didn't have anything else, so is all I could do. Then my neighbor came with his tractor and tiller. Wow, we really had a good garden that year. I think I'll get the sub-soiler out this weekend and start going over the garden getting it ready for some corn planting.