Originally Posted by HansTWN
I think the main difference is the way I read. When I read a book I take off my glasses and hold the device quite close to my face. When use a tablet for browsing, reading the newspaper, or watch a video I hold it much farther away. With my laptop the distance is even greater. And the closer I get to my eyes, the less comfortable I feel with LCD screens.
This is why dpi is so important. Your laptop screen most likely has a resolution around 100dpi (a 1080p 15" screen is only 140-ish dpi). That's way too low resolution to read comfortably on, especially if you're holding it right up to your face. An iPhone 4/4S/5, iPad 3, Galaxy III S, Nexus 7, etc (basically any modern high-end phone or tablet) will have dpis well above twice that of your PC, possibly even three times or more.
Start with a high quality device, add a high quality reader (I like Aldiko on Android), switch to "night mode" (white text on black background), and adjust brightness and font size as needed and you may find LCDs a lot more comfortable to read on.