Sadly, a couple weeks ago, I pulled my Kindle DX from its protective case and I discovered the 5-way control button had spontaneously cracked. I contacted Amazon and they sent me (for a little more money) Kindle DX Graphite--the newer model DX. As you can see here:
They wanted me to send back the old-broken unit,
so I thought I'd record my side-by-side experience while I had them both
in hand. The original unit is on the left, the new DX Graphite is on the right. (If you know what to look for, you can see that the 5-way control button has cracked. I hope Amazon used a better quality plastic in the Graphite.)
My son and I had a little argument about the display quality. Had it improved? If so, how much? My subjective opinion was that it was subtle, but a small improvement. Nevertheless, the argument prompted me to use my microscope to find out.
The following images show the e-ink display under a low-magnification:
I also compared the displays with high magnification:
To be fair, my Kindle DX is years old and my DX Graphite is brand-spankin' new. Will the DX Graphite display quality degrade with time? I don't know. Ask me in a couple years.