I have the King Kutter 30 inch scoop. It works real good - now. The first time I tried to use it, it wouldn't dump. With it full of dirt, there was too much resistance and the trip lever wouldn't slide. There is a roller on a bolt at the bottom that the bottom of the trip lever rides against and the bolt was too tight and wouldn't allow the roller move. I removed it, greased it real good, and put the bolt back on and didn't tighten it down as much so the roller can roll. Now it works great. Use nylon for the pull cord so it will slide easy. Some people have modified it by eliminating the rope and welding bar on the lever so it can be reached from the tractor seat, but that only works if you don’t ever reverse the scoop.
I’ve only used mine by going in reverse and have only dug down a little over a foot. I was able to dig in sod by angling it down. It is possible to dig deep with one, but only if it’s a wide hole because you have to get the tractor down in the hole as you go, so you can’t dig a hole with very steep edges. I’m planning to use mine to dig out a crawl space for a 14 x 16 foot room addition. I only have to go down about 2 feet, so I think I can do it with the scoop. But, I’ll have to do the edges by hand with a shovel. I’m also planning to add a hydraulic top link before I attempt this job, so I’ll be able to control the angle of the scoop from the tractor seat.