See the comment I added later.
I've own this brand and have used two others. If you are shopping for a way to remove mud and leaves from footwear - before tracking it into the house (short-route to divorce court) - here are some tips.
1. All boot scrubbers must be secured in place, usually by anchoring to the floor. Look for heavy-gauge scrubber frames with holes that will allow bolting the unit down. I found drilling and bolting through a wooden deck, step or concrete block worked best, as the vigorous back-and-forth scrubbing action eventually loosened lag screws set in anchors.
2. Anyone standing on one foot while pushing and pulling the other foot (especially a wide or lugged boot) through a boot scrubber will appreciate having a sturdy handrail, banister or wall for support. Leaning against a wall in front of you is okay, but... (read on)
3. Mud, sleet and leaves (or any other nasty stuff you stepped in) are removed by stiff bristles. Some debris falls down into the scrubber frame, so look for frames that do not mount flush with the floor on all sides, so you can flush or blow the debris out of the center easily.
4. Approximately half of what is removed from your boot does not fall into the scrubber frame. The rest is "flicked" by the stiff bristles some distance ahead of and behind the scrubber.
5. Vacuums are fine for cleaning up dry debris, but stuff removed while still wet tends to be more "adhesive." You'll probably want to be able to hose this area down occasionally, so think about that when choosing a scrubber's location.
6. Some scrubber frames are taller than others; this allows debris to be sprayed even further by the stiff bristles (anticipate several feet of spray zone).
7. I found brushes mounted on taller brackets (brackets with legs) harder to use.
8. Fiebings's brushes held by wooden brush-heads, so they won't last if left out in the weather: the wood warps and cracks. Brushes held in plastic brush-heads withstand water and mud better, but intense sun will still shorten service life.
9. Metal scrubber frames and bolts will corrode eventually, but nylon ones turn brittle and break. Either happens faster if left out in the weather and sun.
10. The stiffest polymer bristles are best for removing caked on mud, but can scratch soft (wet) leather, so if you care about aesthetics, or are cleaning your dress shoes, beware.
11. Having all the bristles the same length makes it harder to reach debris trapped in a heavily lugged boot sole. Consider trimming some bristles down by the depth of your boots' lug patterns, to allow longer bristles to get deeper between the lugs of the sole.
12. These scrubbers all seem to be made for shoes on feet of average size (man's sizes 7 to 11), so entry width between brushes is an issue.
13. A few scrubber models have tapered openings (wider at the bottom) between side brushes, to allow for the usual shape of most shoes (widest at and near the sole).
14. As heavy work boots and overshoes can be much wider than shoes made for everyday wear, the width of many boot scrubbers is too narrow for some footwear, especially true for larger-than-average foot sizes. My work boots (size 15 EEE) are definitely too big to easily wipe through these brushes, even with the unit bolted down. Someone should make an adjustable (expandable bottom frame) model; until they do, consider trimming the length of the bristles. Trimming will also make them stiffer, and more likely to scratch soft leather. I am considering cutting a scrubber frame in half, drilling some holes and adding a piece in between to extend the width while maintaining the frame's rigidity.
15. Having a boot scrapper (handheld or anchored) is still best for getting mud and snow (or even much nastier stuff you may have stepped in) out of the area just forward of the heel. Stay married... clean your boots before going inside.