I use my iPad and my Kobo for digital reading. I have paper version of "important" books (stuff I'd like to read if I don't have power), but some are unwieldy (Algorithms by Cormen et Al).

I prefer e-ink for reading, but it's too slow for my learning workflow. I highlight and mark interesting stuff, that I export later to condense and reflect upon. And that is cumbersome on an e-reader. There's also the matter of size. I generally like the PDF version of technical books as they're typeset well, but my e-reader is too small for them. So I use my iPad for those (Distraction is handled by the fact that I read those in short focused sessions).

But for fiction books, the e-reader is perfect. I don't highlight text in those books, I just read. Any other operation is slow enough that I just can't fiddle with it. And it's perfect for long sessions of reading as it does not project light in my eyes. It's light, so I just bring it with me everywhere.