I still use CHM document as it is absolutely the best solution compared to anything else. I think it is a mistake to compare CHM with PDF... They are made for different things...
I forgot to mention - I use CHM on Linux. It is not my fault that opensource community could not come up with a better or/and standardised solution... The only standard solution for this that Linux has are man pages - clearly not suitable this purpose! Other, better solutions are there, but are not adopted by all - Gnome has one format, KDE another, etc... CHAOS. Therefore, I decided to use CHM.
