Probably a great display, the most competent contender likely being already available Gigabyte M28U, which unfortunately costs about 800 €. 4K is a sharp resolution, but it's hard to imagine someone paying more than 200 € extra just to get 4K resolution over QHD models. Other aspects of image quality likely are not that much better compared to 400 € monitors. Even 600 € would be rather steep, but once monitors like these hit 500 € they become significantly more popular.