> I mostly have issues with epub like formats. Epub is great for content that is mostly texts (Novels,…). As soon as there are objects that need to keep their

> I mostly have issues with epub like formats. Epub is great for content that is mostly texts (Novels,…). As soon as there are objects that need to keep their relative distance to each other (equations, diagrams), I go for PDF. It's also not easy to get good typesetting for epub files. I believe that typesetting gives you a visual map that provides an additional memory boost. Doing focused reading on a phone is a no-no for me. I use my tablet for PDFs and my e-reader for epubs.