Mainly used to study from textbooks. Annotation function with highlighter should not with every highlight ask to increase or decrease the size of the highlight, if you are highlighting multiple lines in a long text, this is useless and cumbersome. Large textbook files hang repeatedly and dont save the highlights. Positives: scrolling function is good and responsive. Nice array of colours for highlighting and annotating and drawing on pages. Would be nice to have a setup like a library.