The star, of course, is the XG-2700-4K, a 27" 2160P, UHD, monitor that packs FreeSync compatibility with a 60Hz refresh rate. Around back it has a DisplayPort 1.2a connection, mini DP as well as one HDMI 2.0 and 2 HDMI 1.4a inputs FreeSync is only supported via DisplayPort, but with the announcement of FreeSync over HDMI, it's possible to provide that functionality with a firmware update. Beyond that, ViewSonic has their SmartSync technology that seems to a platform agnostic, scalar-integrated, method of keeping the best refresh rate based on what's being input. It does sound a lot like AdaptiveSync, however.
The panel they're using is what they've termed a SuperClear IPS panel that has a light anti-glare coating on top. It's likely an 8-bit + FRC LG panel. Input lag is supposedly very low allowing for the FreeSync to have a much more pronounced effect, even with it "only" being 60Hz. ViewSonic is also touting their Black level stabilization technology, which controls the contrast and makes darker scenes more easily visible. And what else is there?
They've pioneered a few game modes that you can select depending on the genre you're playing that are supposed to optimize color, brightness and contrast to values that are commonly used in those situations. Even if you don't intend to use those modes, this 4K, IPS, FreeSync beauty is for sale right now for $699.