My Gregory grapple beats it easily. This tool is having trouble penetrating the soil around the rootwad, and that is why the operator is ramming into it, and actually spinning the tracks in moderate conditions. Also it lacks gripping power, vs the Gregory.
It kinda looks like a set of forks turned sideways on edge, so ground penetration is easy. Then when you feel the root, simply close the grapple right through the soil, and get a positve grip or encircle the root. Now by lifting straight up or levering, snap it. Go around the tree right quick and repeat a few times if needed. Grab the stump by the top and lift out, shake it to drop the dirt from the roots back in the hole. If you have too much dirt you can pinch it out to dry out the stump wad for burning later, or just to make it lighter for lifting/hauling. Some old stumps, or smaller ones just lift out without digging, depends on the soil, and what kind of tree, etc. Also neat for popping out roots in a lawn with minimal damage to turf.
And you do other neat jobs with it, like snapping out concrete for example.