I really hate PDF for many reasons. It seems it's only a partially open format, a lot of features are implementation dependent (how can a file be 'locked' to pr

I really hate PDF for many reasons. It seems it's only a partially open format, a lot of features are implementation dependent (how can a file be 'locked' to prevent printing or editing?). There are very few free and FOSS clients that handle forms, highlighting, etc. Some clients do highlighting and annotations but don't save it to the PDF itself. The failure of epub and other HTLM based formats in this use case, IMO, is that their focus on reflowing to support any display and device makes them inconsistent and therefore impractical for replacing PDF based content.