I've been sent a couple of very large PDFs in which the fonts aren't embedded properly. They're either missing, or the Adobe Serif MM has been used and embedded instead. This can cause the fonts to display and print poorly.
Using the Preflight "Embed all Fonts" didn't seem to work, so I decided to export as PostScript, then Distill again, which seemed to fix everything.
However, the documents were several hundred pages, and had extensive Bookmarks. These bookmarks were now lost in the re-Distilled version.
The solution? Replace all the pages in the original PDF with re-Distilled PDF. Bingo: Properly embedded fonts, with all the bookmarks.
There may be another method (export pdfMark in the .ps?) but I couldn't find it, and I thought if anyone was in the same boat, they might like to know this. Obviously, in an ideal world, I would get the creators to re-supply, but they showed no interest.