From a user's point of view, PDF is a good experience, at least for highly formatted documents. By this I mean documents for which the specific layout, placeme

From a user's point of view, PDF is a good experience, at least for highly formatted documents. By this I mean documents for which the specific layout, placement, and aspect ratio is an integral part of the authorship. A comic book/comic strip or a diagram meant to be viewed a certain way are examples of this. Lots of the technical books I have are designed such that to change their visual presentation would require changing the actual content. Like it or not, there's tons of pre-existing content designed for a specific presentation, and PDF (or postscript) are a good choice for that. The biggest problem with PDF is that it usually requires a specific page orientation and aspect ratio, if not a specific page size. This is okay if you have a large enough display and can resize your viewer window to suit, but it's a bit more of a problem on smaller displays, or irregular shaped or resolved displays. For those, a liquid layout and typographic styling, something like HTML or ePub makes much more sense.