I didn't used any of the PDF:: modules yet, only have some experience with the Apache FOP generator, but I would bet that they are not able to compete with LaTeX PDF output, as long they aren't using it as back-end. FOP can't, at least what I saw so far, maybe with better settings it gets better.

I'm talking about document layout quality. Most tools only translate tags from one format to the other (e.g. HTML to PDF) which results e.g. in poor page breaks and ugly spacing.

For longer documents I would generate LaTeX code from Perl and compile it with pdflatex. The drawback is that you have to know LaTeX for this. But this could be wrapped into a modules, maybe there is already one on CPAN.