Fit to screen is available in books and PDFs, though it barely changes the margins in books (ePUB). It certainly does a good job of removing margins in PDFs, but text is still quite small in portrait mode.
Full justification seems to depend on the book: Stephen King's Skeleton Crew = yes, Dan Brown's The Lost Symbol = yes (don't shoot me for mentioning that book
), one of the free Sony classics now updated to PDF (Moon and Sixpence) = no.