Formatting for print is one place that's still a bit tricky. Not much control over how browsers will print things, though some people I know have had success with PrinceXML as a print converter. Doing lots of "normal" print things like referencing page numbers is a bit unnatural as well, e.g. replicating the LaTeX \label \ref pair that lets you write things like "(see page 256)" without hard-coding it.