I have a 7.5' Rhino, 18" bucket on a Kioti CK25 with loaded tires. First, these are not nearly as capable as an industrial backhoe. Don't expect it to toss around a 2000 lb stump. They aren't well suited to removing big stumps. They might do it, eventually, and it's pretty hard on them. However, they are quite effective for most homeowner needs, including stumps up about 15" or so. I think frame mount is imperative, as is loaded tires. Weight is king to keep the tractor well planted, else the hoe will push/drag it around. Good outrigging pads are essential too.
Tractor hydraulics plays a big role in performance. You want as much flow as you can get, at the highest pressures supported by the equipment. Rear remotes is the best setup to run the hoe from.
Reach is also important. Get the longest one your tractor can safely operate, else you'll be constantly moving the tractor and in some cases you just won't be able to reach what is needed, thus requiring manual digging or other such horrors.
Mine dismounts easily, in less than 5 minutes. Mounting is a harder, as you only have about 3/4" of side-to-side alignment allowance. Typically takes me 15 minutes or so to put it on, most of the time is just getting the tractor aligned with the mounting hooks.
Storage is a consideration. Mine is about 6' wide x 12' long when off the tractor, and of course immovable without machine. No matter where I put mine, it always seemed in the way. Had to finally build a structure just to store it in. So, if you plan to take it off, remember it doubles the storage space needed.