I'm hanging fire till monitors with hdmi 1.4 arrive which is where the current bottleneck is that's stopping 4k monitors from going above 60hz. My gtx 1080 will not hit above 60hz too often at 4k but a monitor like this is a 10 year investment that should easily outlive your current card. Heat for the deal as its as good as you'll get right now.
I have the XB271HU and can confirm it's absolutely beautiful, especially with high FPS.
I've got the 27 inch version of this as well as two of its 1440p cousin the XB271HU IPS, if you're happy to size down a little I'd honestly recommend the 1440p version, it's superior in every way - 144Hz, easier to drive, overclockable. These 4K Predators have an issue where half of the panel will spasm out every half an hour or so. The panel consists of two halves, so they fall out of sync every now and again. It's present on both the 27 and 32 inch models: https://community.acer.com/en/discussion/456382/xb271hk-flickering
In a different category than this but might interest some: https://hothardware.com/news/philips-momentum-43-monitor-4k-displayhdr-1000-amd-freesync
Nope, it was futile. I'm sure this site costs me more than it saves (skeptical)