Getting a lot of ads for this in my feeds, any opinions on usefulness/quality?
I’ve seen these ads too. 
I would put it in the category of: overpriced bells-and-whistles gadget that is as fun to play with as it is to use for its intended purpose…
Though as high end executive paper-weights go, at least this one has a technical function.
If it actually is manufactured with good tolerances and can hold repeatable indexable angles? Tons of small-part clamping possibilities may justify the price.
I’m not buying one until I see yours firsthand, first! 
I’m just concerned that all those moving parts and tolerances are going to be a huge maintenance pain for any hobby that sheds any types of particulates… If you enjoy taking apart watches though, the teardown for cleaning of this vice may speak to you as its own joyful endeavor! 
I’ve only bought into one kickstarter….never got the product but they did send me emails asking for money for their next great project. O.o