QuoteAsus is also sticking to the RGBW pixel grid to provide more accurate colors at the cost of some contrast
That isn't what the RG/BW grid does at all. The RG/BW grid is a cheap trick to produce a less-sharp display that can still be advertised as a particular resolution based on the outdated technicality of defining resolution by contrasting line pairs instead of individual fully-colorable pixels. A normal display puts all three primaries (RGB) in each pixel, whereas this display chops that up into alternating "pixels" each containing either red and green, or blue and white. No square contains all three primaries at once, and in many cases that added white component dilutes color rather than making it better.
The ASUS UX501VW-DS71T should not be given the advertising privelege of 3840x2160 because it's not 3840x2160. It's not some sort of lesser-4K-but-still-4K type deal, it's literally not 4K because it's not a grid of 3840x2160 individual fully-colorable squares. Doesn't mean it's a bad display, but it's not 3840x2160.
It's awesome that you guys have begun to include the subpixel arrangements in these reviews. I think that's really important. But I think it's also important to properly describe what these displays are, and what they aren't. Deceptive pentile display advertising is a significant issue in the laptop market today, and laptop manufacturers / sellers need to be called out on it when it happens.