Any 3-point Post Hole Digger is next to worthless in my opinion. I had a Bush Hog 2102 with a 12" auger that I had plans to drill numerous holes with.
As plans changed, I only drilled 12 holes with the PHD before trading it in as a down payment on a JD L130 lawn tractor.
Connecting and disconnecting a 3-point PHD is a royal pain in the butt, and they aren't quick-hitch compatible. The dealer describes connecting and disconnecting a PHD as "Wrestling with an octopus." Excellent analogy! Where I live, bentonite soils are real common and I call the stuff claycrete. I got my PHD stuck 4' down where the gear box was at ground level. Unlike a hydraulic PHD, a PTO PHD can't be reversed to back the auger out. I thought I was going to have to flag down a guy with a real backhoe or front end loader to pull this thing out; but I managed to rock the auger back and forth a bit to extract the auger with the lift arms.
If I need more post holes, I will hire someone to do it or rent a hydraulic PHD, or if I get the itch to own a PHD again...it WILL be a hydraulic powered unit.