I'm surprised the article didn't address backlit screens vs front lit or traditional print. Eye fatigue is a massive factor that effects our reading habits. In fact, I'd wager it's the ONLY factor messing with how we read on devices versus not.
I know personally I cannot CANNOT read for content from a back-lit glowing screen. I can skim, browse, read short news articles (that yes, I probably read non-linearly like the article says) but when my art history professors dropped a few ten page articles on us every week to read, I HAD to print them out and read them on paper. People looked at me funny when I showed up to class with my binder of printed out articles, but I darn well know I got more content out of them.
I own a Nook Simpletouch with Glowlight for my digital books. It's that E-ink display so it looks like regular soft-cover book/newsprint paper when you view it. When you turn on the glowlight, it's a front-light. Meaning the wee LEDs shine light on the front of the surface from the edges. Eye fatigue is non-existent compared to my mom's glowing Nook tablet thing. She can't read on it either and it's changed from a "take it on the boat to read while your dad fishes" machine into an AngryBirds and Facebook machine.