I think there's a difference in behaviour both by the type of book, and the device you're reading it on. I've had a sony ereader for about 6 years now, and I read fiction on it. I like it because the battery lasts forever and it works in direct sunlight - if I'm going on holiday, that's the device I make sure I have.
I also read on my phone because I always have it with me, and I don't need a separate booklight for it, so if I find myself stranded upstairs putting a baby to sleep then I still have something to occupy me.
I like both because the SF authors I read seem to like using unusual words, and being able to click on them to find out what they mean is really handy.
Both of these are fiction though. For reference/educational I prefer the paper - it's easier to flick through, I can put post-its in as mentioned above, and I find it easier to scan. A tablet is a second place to this, I just find I need the bigger books, space to stretch out when I'm reading something technical that a phone or ebook reader doesn't seem to give me. I don't know why.
Then if I want searchable reference I go online with my computer or a tablet....
I may just be over-teched :D
The safari bookshelf is a great resource for techies - like netflix, but for books.