Has always worked for me when printing pages FF had a problem with. Five stars if it had an "Auto" setting to insert page breaks ON EVERY PRINT JOB, without user intervention.
PDF is getting ever more useless at reliably saving page contents. I don't care about pretty, but I want the whole text - the most recent example is the eBay checkout page that confirms my orders; only headers print, everything below that's larger than a single PDF page is now missing.

Edit: To be more specific, I print as HTML to a PDF printer, not using any Print-to-PDF plugin or function.