XML::Parser::Lite is designed to parse SOAP messages, which encompass only a subset of XML, so I would definitely not use it as a generic parser. XML::SAX::PurePerl is a generic XML parser written entirely in Perl.It is quite slow but this probably doesn't matter for you. And if you use XML::SAX you can always replace it later by a faster parser.

BTW SAX is a standard api for processing XML in stream mode:it looks a bit like XML::Parser's basic api but is more recent and more powerful, especially when it comes to namespace processing (which you probably don't need right now). The most important features of SAX are that as it is standard you can swap parsers, go from a Perl one to a C one (like XML::libXML) or even use a parser that generates SAX calls from a non-XML source, such as Excel stylesheets (XML::SAXDriver::Excel) or CSV (XML::SAXDriver::CSV).