The iPad has a killer feature: in landscape mode it shows the book as two side-by-side pages.
I suggested this idea on this forum a year or so ago for the DX and was met with silence.
Apple gets these small details right. The backlight can be dimmed all the way to virtually off and the app store has the Kindle App so your Kindle library is available.
The iPad is the clear winner and Amazon still gets revenue. My Kindle was sold about two months ago.