Unfortunately, I see the fast deteoration of our civilisation. At this speed we are done in a few years/decades. Stupidity and ingnorance rule the world.
Back to e-ink readers. To my opinion white frame of M92 is quite OK. It would be better, if it is few grades darker.
Grey or black frame creates the feeling the white of e-ink is whiter. I tested it on Kindle DX (gray frame) and M92 (white frame). Kindle seems to be a bit whiter than M92. But if you cut a paper frame to simulate a white frame on K DX then both displays are the same/comparable.