My neighbor loaned me one that he bought from Harbor Freight. It powered through dirt just fine. But I discovered my land is nothing but 1/2 fist to fist sized rock covered with a veneer of dirt. I had to use a metal rod and mini sledge to pound rocks out of the walls of the holes a lot to be able to continue digging. 2 deep holes for a trellis and 2 shallow holes for muscadine and 4 shallow holes for blueberries and I had 1.5 5 gallon buckets of stones.

So yeah, if the ground isn’t rocky they work great. But if it is, it’s still a ton of labor