I've been running Hopey steering dampers on my snowbikes for ~10 years. I've written a lot about them here and elsewhere so I won't belabor that point. Essential, in a word.
Tried a Hopey on a dirt/mountain bike once. Once. Hate is not too strong a word. Bled, finished the ride, then removed it.
The Viscoset is different. Similar idea, different execution. Stacked one on top of the Hopey on my snowbike last winter. Loved it. Ran 'em both at full max damping. LOVED.
Installed it on this Fatillac on a whim. Figured I'd ride it once, hate it, remove it, and call it good. Nope. Running it at full max damping.
So far I notice a lot less wandering of the front wheel when climbing. And a lot less oversteer in corners.