in reply to Definitive/Favorite Perl XML DOM + XSLT interface?
However now there's a new contender - XML::GDOME, which builds on the libgdome library to provide a full implementation of W3C DOM level 2. If it's conformance you're after primarily, I'd go for GDOME. However I really think you'll miss access to XPath (though that's intended to come with the next release of XML::GDOME, so you may not be waiting much longer).
As far as XSLT goes, you really can't beat XML::LibXSLT for performance and compliance. It's almost as fast as MSXML's XSLT implementation (the known fastest one), and supports exslt extensions and a number of other niceties.
Also, I have yet to try it, but I hear XML::GDOME can now convert a tree to XML::LibXML format, which will allow you now to use XML::GDOME trees in XSLT transformations. Neat huh?