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 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,
Java™ 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.