Adobe Mars: a counter-strike against Microsoft's XPS
Adobe announced a new file format, code-named "Mars": an XML friendly representation of PDF documents. The Mars file format incorporates additional standards such as SVG, PNG, JPG, JPG2000, OpenType, Xpath and XML into a ZIP-based document container.
This seems like a direct counter to Microsoft's XML Paper Spec (XPS). Microsoft was positioning XPS as a XML-based competitor to PDF.
I guess I don't see the real value in "XML tools": both of these formats are far too complex to do any real work with plain XML tools: you need higher-level tools/libraries/APIs. And those higher-level tools could just as easily generated PDF directly.
As long as the end result can be directly converted to a PDF, I would treat it as just another library to help create PDFs.