I have a Wallenstein Trailer.
It can be use as a log trailer to haul out logs for firewood, building WOFATI's, setting rafters and timbers in place, picking anything heavy, moving big round bales, or any other number of things. But then the grapple can be changed out and a post hole drill put in its place so you can bore fence posts, posts for WOFATI's, or any number of things. But then the log bunks can be swapped out for a dump body that comes with it, so you can move brush and dump it, place big rocks you have picked up with the grapple in the dump body, or fill the dump body with soil or gravel to build driveways, paths, move manure, brush for hugels, etc. But wait there is more. You can then put a backhoe bucket on it so that you can dig trenches, make swales, make hugels, cover WOFATI's, etc.
I am in the process of building an upside down woodsplitter for it so that I don't have to lift firewood at all.
In short it is the swiss army knife of homestead equipment. And with its own 6 hp engine driving the hydraulics, it is self powered. I use it on my bulldozer, farm tractor, but honestly use it the most on my Ford Explorer! That is because it is so fast, can go down the highway, and is so versatile. Besides my bulldozer, it is the second best purchase I ever made.