This is an excellent shoe scraper.  However, to work effectively, it needs a base, which is not easy to attach.  Apparently you can remove the bottom brushes and use the drill holes, which I did not figure out.  I screwed a piece of scrap board into the bottom brushes from below (through the drill holes), which works fine, but requires fairly exact measurement.  The board extends @ 9 inches to each side of the brush.  I stand on the board with my off foot so that it is firmly anchored when I brush each shoe.
The fit is very tight, which is necessary for the brush to remove debris thoroughly.  I suspect that reviewers who complain of the tight fit for large shoes have not attached an anchoring board.
The product would be improved by the inclusion of instructions for attaching an anchor board.
Because I have a small back porch, I have to keep the apparatus a few feet away on a paved surface.