For Mac/Windows, I've heard that Devalipi is good.  https://www.devalipi.com I use Montax Imposer, Windows only. http://www.montax-imposer.com Montax has a size-limited free version. I don't know its other limitations, if any. Imposition software doesn't change any thing about the internals of a pdf, only rearranges the single page type pdfs for imposition (along with creep, signatures, etc.).