I like what you can do with PDF too, that's why I uploaded some books in PDF format (
see these). But PDF is good for self-consumption, not so good for distribution, unless you create at least a different version for each screen size (and then people will ask for different font sizes, different line spacings, margins, screen orientation...).
A compromise solution is creating PDFs from ePubs, with the
Prince PDF calibre plugin. You can distribute an ePub and embed some settings that will allow anyone to create an acceptable PDF version too.