More news on support for XPS and interop with other formats. Nuance announced version 5 of PDF Creator earlier today (press release) with support for converting between XPS, PDF and editable formats, including those supported in Office. From the product details page:
New! XPS input and output
Load XPS files and convert them to editable formats, or convert your PDF files into XPS. XPS files are handled in their native format. No other software component is required for the conversions.