I have one of these and an Achieva Shimian 1440p (newer 2700 model not 270) side by side and here's what I notice:
(Shimian as a reference point, not as a direct comparison since 1440p =/= 4k)
Pixel functionality: 1 stuck on the crossover, left middle, green color. 2 small clusters on the shimian. Crossover wins.
Color accuracy: side by side, the Shimian is noticeably better even after an hour of tweaking (by eye). Shimian wins.
Viewing angle: Shimian wins, slight green color shift for the Crossover. Not serious though.
Brightness: Shimian wins, 50% is brighter than 100% on the Crossover.
Build Quality: Tie. Crossover has a nicer stand but Shimian has vesa screws pre installed (which was very convenient for me)
Response time: I'm fairly sure the Crossover is actually faster with PQ set to bypass and source manually set to DP 1.2. No empirical evidence, just some half baked tests with half a window on the Crossover and half on the Shimian. But at least I can say it's not a problem for me even while playing CSGO. Crossover wins.
OSD: Crossover wins, remote is useful for menu navigation, updateable firmware, more features.
Connectivity: Crossover wins, more ports and HDMI 2.0. (I didn't test to see if HDMI 2.0 actually works though.)
Bezel: Crossover wins, slightly more than 1cm bezel vs ~1in for the Shimian
Price: Crossover was twice as expensive.
Notes: I get motion sickness with the XOver with certain games...probably caused by larger panel + lower framerate due to 4k. Text is pretty much the same size as it would be on a 15.6" 1080P laptop screen (it would be equivalent to a 31.2" 4k if you do the math).
Overall I'd rather have 2 Shimians than 1 Crossover if I was going to spend $440 on monitors. But that's just me and I also don't regret buying the Crossover. If you don't have room for multi-monitors, then go with 1 Crossover.
Edited by a300 - 2/3/16 at 6:00pm