which emacs mode for V5.0? nXML or psgml

Which is the preferred mode for editing DocBook V5.0 docs? Which is
the most popular? Is psgml being deprecated? Does psgml have a lot of
features that are missing in nXML? I've got nXML working with a
V5.0CR5 docbook.rnc. It seems pretty good.

I wanted to try out psgml to compare, but I haven't got it to work. My
test file is below. If I run sgml-parse-prolog it seems to run without
errors.

If I C-c C-o I get ``XML is not in any name group for element
ARTICLE'', pointing to the : in xml:lang in the article tag.

If I make the article tag simply <article> I get ``Start-tag of
undefined element ARTICLE; assume O O ANY'' from C-c C-o.

I wonder if the problem is with the "file:/home/jra/..." in <!DOCTYPE
.... If I make it "/home/jra/..." (no file:) or "file://home/jra/..."
(use //) I get:

sgml-error: Name expected; at: :id	ID	#IMPL
 - line 2 col 11 entity db.common.attributes
 /home/jra/usr/DocBook_V5.0CR5/docbook.dtd line 42 col 30 entity ARTICLE
 /home/jra/Projects/Side-Projects/docbook/test-dtd/testdoc.sgml line 2 col 101

The line in the dtd it is complaining about is:

<!ATTLIST title
	xmlns	CDATA	#FIXED	"http://docbook.org/ns/docbook"
	role	CDATA	#IMPLIED
	%db.common.attributes;        <------- THIS ONE
	%db.common.linking.attributes;
>

Any ideas? Is it worth looking into psgml, or should I just run with nXML?

Thanks, Jason

<?xml version='1.0'?>
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V5.0//EN"
"file:/home/jra/usr/DocBook_V5.0CR5/docbook.dtd">
<article xmlns="http://docbook.org/ns/docbook" version="5.0" xml:lang="en">
  <info>
    <title>A Title</title>
  </info>
  <sect1>
    <title>A Section</title>
    <sect2>
      <title>A Subsection</title>
      <para>
        Xxxx xxxxxx xxxxxxxx xxx xxxxxx xx xxxxxx xxx x x xxxx.
      </para>
    </sect2>
  </sect1>
</article>

<!--
    Local Variables:
    mode: sgml
    End:
-->