XMLmind XSL-FO Converter 
is available embedded in
XMLmind XSL Server, a powerful, production-quality,
Servlet 
which leverages the
XSL 
technology
to allow converting XML documents to a variety of formats.
Out of the box, it allows to convert DocBook 4.x, 5.0, 5.1 and 5.2
including
assemblies 
and XHTML documents to PDF, RTF (can be
opened in Word 2000+), WordprocessingML (can be opened in Word 2003+),
Office Open XML (
.docx, can be opened in Word 2007+) and
OpenOffice (
.odt, can be opened in OpenOffice/LibreOffice 2+)
formats.
DITA 
1.0, 1.1, 1.2 and 1.3 documents can be
converted to even more formats: XHTML 1.0, XHTML 1.1, HTML 4.01, XHTML 5,
Web Help, HTML Help, Eclipse Help, EPUB 2, EPUB 3, PDF, RTF,
WordprocessingML, Office Open XML, OpenDocument.
XMLmind XSL Server targets the Web developer (JavaScript, Ajax, PHP,
etc) and the system integrator.