Used to use them a lot back in my landscaping days. They are a great tool for lawn installation, but are not for deep tilling. When installing a new lawn, we would first correct whatever the excavator left as their idea of a "finish" grade. Next came a couple passes with the pulverizer to loosen the soil and break up clumps. This was followed by a pass with the rock hound to remove all of the stones at the surface. Last came seeding, fertilizing, and straw.