I think they're a good concept other than that the 'dozer' blade part of it is not suited to a tractor. If one were made something like a half-depth (short bottom) tooth bucket for more powerful digging/prying and then a 'bucket extension' sort of lid and both had more useful gripping designs on the side walls, i think it would be better suited for a tractor. But i agree that buying a skid steer 4n1 is probably not a good idea unless you put it on a huge tractor, or you're buying one for a mini skid steer (smaller, lighter, but still commonly up to ~54" wide) and modifying it to suit. I considered following that path for my B8200 but decided if i'm going to do it at all, i should just build it the way i want it, which is halfway between a dedicated 'tine' bottom grapple, and the usual 4n1.