I find it funny that "military grade" is so far from true military grade.
The only thing they probably share is the caps, and IC, but after that its completely different.
I remember on XS some guy had somehow managed to get a hold of a server that was used in Iraq.
The thing was cooled by liquid gallium using a magnetic pump because a normal pump wouldn't work reliability when and if the metal was to cool down and solidify during the nights.
But -- what is "military grade?" I assumed that the Pentagon has a MIL-spec for motherboards. But all I really know about the ASUS Sabertooths are these things.
The boards are a tad thicker than some of the other models, probably with exception of the top-end flagships.
ASUS and some reviewers noted that the components were superior -- solid state capacitors, etc.
the boards came with a 5-year warranty.
I only bought one Sabertooth in my experience as brand-new in-the-box purchase -- the one I currently have. It's been the absolute best, so far, even if the phase-power-design is 8+4 instead of 12+4 or the 16-phase spec of the boards more expensive than the Sabertooth.
But now, there is no more Sabertooth. there is only "TUF."
ON THE DISCUSSION ABOUT THE DUCT-PLATE
The duct-plate should improve board-component cooling if you can assure enough airflow into the cavity between board and plate and out of it -- preferably with directed, restricted airflow over hot items like the chipset, VRMs and similar components.
I had bought the cheaper Sabertooth Z170 S without the duct-plate, and built my own. To some extent, mine would seem less effective because it sits off the board by about an inch, as opposed to what looks like a quarter-inch. But it works for me . . .