Ha ha, trick question, there is no “best” templating system except for the one that’s best for your project.
Vince Veselosky has a roundup of Perl templating systems where he examines everything….

… from the Swiss Army Chainsaw of Template Toolkit, through HTML::Mason and Text::Template down to the ever-tempting “variables interpolated in a here-doc” method….
Read on for a comparison of the major template systems in Perl, and my recommendations of which systems fit which circumstances.

It’s a fine introduction to the various systems, and probably worth pointing to from the Perl 5 wiki, if not reproducing it there entirely.