For the article, I'd be interested in a recommendation for Gsync vs ULMB.
Well, here's my take on it (completely uneducated, just my observations.. hehe):
I've got the Asus XB270HU, G-sync, 144Hz. As mentioned above, I think ULMB only works at fixed framerates (locked to the monitor) and can't work alongside G-sync because of the variable framerate. I read an article just now that says my monitor can run ULMB at 120Hz, which would work for a game that's locked to 60fps. But, apparently earlier versions of the monitor couldn't do it, so YMMV.
That said, this monitor doesn't seem to have any blurring issues at 60fps anyway.. I don't notice the effect until the framerate gets up around 100 or higher (probably because the monitor's refresh rate is so high to begin with.. G-sync monitors that cap at 60 may be a different story entirely). I've been playing DS1 at 60fps and it's flawless (thanks, Durante!). Given that the effect might not really exist for me, the choice of G-sync is obvious, since it will keep the game nice and smooth even if it dips down into the 40s or 50s, and none of it will have any motion artifacts from the monitor.