I think the flicking back to remind myself of things is why I prefer paper books for non-fiction. Also, a lot of the non-fiction I read is the sort of thing that has maps in and paper books also allow me to flip back to the maps as needed.

I've never really got on with hardbacks, and actually one of the really good things about ebooks is being able to read books I'm excited about as soon as they're published without having to choose between buying a hardback that I'll find awkward to read and waiting for the paperback to come out. (Sometimes, I then buy the paperback later so I have a copy to re-read.)