What is, besides Foxit's PhantomPDF, the greater, greatest and most complete alternative for a PDF editor with an emphasis on Preflight, PDF standards and PDF/X. I would require also operations to convert color spaces and make output intents for printing. (Basically, the whole functionality of Adobe Acrobat, but better, more efficient and without it being from Adobe.)
A program that is not so much focusing on manual editing, but completely on Preflight and conversion would also be considered.