Philballer17 :
IF you're asking for the very best paired with an Nvidia Graphics Card.
ASUS PG278QR / PG279Q.
There is also a curved option in the ASUS PG27VQ.
Anything else is pretty much below the best. Including any AMD Adaptive sync monitors, simply because AMD is meant to be budget and not the best anyways.
Panels that support free-sync are available with identical quality to the G-sync capable ones. They are just cheaper because they aren't paying for the G-sync module itself (which is a quite expensive FPGA SoC). Not significantly worse in terms of the actual delivered experience. Maybe a tad more latency, but I haven't really seen a competent comparison that really lays it out.
When AMD has a decent GPU on the market free-sync will certainly be more desirable, so hopefully Navi delivers. But Vega 56 and Vega 64 are too expensive for what you get. Though a Vega 56 + Free Sync monitor is now just about the same as a GTX 1070 and a G-sync monitor price wise.
But if you want anything faster, it just isn't there, have to jump on the Nvidia bandwagon and pay the G-sync tax.
I waited for the PG279Q since I didn't like the appearance of Acer's chassis, now it might actually go the other way. Since they source the same panels, and Acer seems to have less quality control issues, I've been recommending them. Also cheaper. Pretty sure ASUS is just milking their brand recognition. There was a time they were the go to company for everything, but lately they seem to be middle ground when it comes to everything.