Mason is complete and non-buggy; no particular reason for updates other than the Perl under it. PHP’s entire approach is a mess and that includes embedded code. This is why not very many of us use Mason and haven’t for a decade: it encourages a PHP-like approach. If you really like that style of code, use PHP. It drives a ton of important sites and with some discipline can be clean.
If you want to see how powerful and easy web programming can be… Catalyst, Mojolicious, Dancer2, DBIx::Class, PSGI, uwsgi+perl, etc. Learning curve but great communities, great testing tools, good awareness of best practices and security. Worth it for the long haul. Maybe not for a one-off.