If it is just for "reading", then PDF of course is the best method.
I can send a PDF attachment to anyone and they can read it. If I send a CDF as attachment, most will will have no idea what to do with it, unless they are Mathematica users and have Mathematica or the player installed on their current device. But everyone can read pdf files and not everyone knows how to read CDF file.
Export to PDF from notebook works fairly well (most of the time :). So if the purpose is just to have someone read your notebook, that is what I would do.
