Firstly, I have not purchased the A-Fab machine, nor am I likely to. I am shopping for a stump grinder having dug out stumps with a BH, but the A-Fab links wave several red flags.
The A-Fab does not have a pivot to allow the blade to tip should the operator take too deep a bite or move forward too fast.
The absence of any reactive movement of the A-Fab vs. videos of the Woodland Mills, Bumalight indicates the the depth of cut must be very small. (Could one tether a belt sander atop a stump, sit down, and sip one's favorite beverage for a more satisfactory experience?)
The machine does not come with a PTO shaft. The required Cat IV, recommended slip-clutch shaft could put the cost up with the Woodland Mills machine.
"The cutting knives must be kept sharp. Dull knives are inefficient and dangerous to use. The design of the unit easily facilitates knife removal and they are easily sharpened and replacements are readily available on E-Bay or other tractor/lawn & garden dealers." No hits on 2 pages with Google "Knives for A-Fab stump grinder"; when I added "e-bay" to the search, the pages I viewed showed Rayco, Greentooth, and other machines, nothing for A-Fab.
"Clear stump of all surrounding soil, several inches deeper than the desired finish height. Clear area of all obstructions to facilitate smooth travel for the tractor." Sounds like "dig the stump out."
Content, grammatical errors, and ambiguous wording in the copy indicates off-shore origin and dubious support.