I really enjoy (and hate at the same time) HTML::Mason. I like it since it is perl based (mod_perl) and does a great job of templating the website, gives a lot of flexibility. But this is why I hate it at times, I do not know the little gotchas that it has and they bite my in my ass. And I have to work and work and work to find a new way of doing something so I can get it done.
The reason I went from it to PHPWebLog last year was I could not get Apache, mod_perl, & php4 to work together. Can they coexist? yeah! but my setup at the time (and still today) does not let me do it. Brian and I have worked on building a new box. Between hardware issues, OS issues and so forth we still do not have the box up. Once we do get the new box in place, we will have Apache, mod_perl, php4 & mod_ssl. Cool. That is when I am going to move my site back over to HTML::Mason.
I can not stay away from the power of Perl.