So I did some new measurements with the i1 Display Pro, here's the PG279QZ
Looks very similar to mine, and the more precise measurements make it seem like AUO is targeting sRGB gamma with most of these (certain batches?) G-Sync AHVA panels.
aren't they both edge-lit considering the panel used?
Don't know, but I think Rtings is incorrect and that Asus is using the same casing and panel since it would be a waste of money for them not to since they didn't change panel suppliers like with the PB278Q which they switched from PLS to AHVA, and changed the casing for in 2014.
Oh, and in my XG2402 adjustments, a third button snapped off. Great and sturdy buttons you got there Viewsonic.
Email them, perchance they will give you something for free or a gift card which never expires; the squeaky wheel gets greased.