Mason has garnered a considerable amount of favor in write-ups appearing in WebTechniques, The Perl Journal, and PerlMonth so don't just take my word for it. It's a component system originally devised to power the CMP TechWeb site, a leading technology publishing operation.The dhandler and autohandler concepts are very powerful ways of expressing template application. For instance, a dhandler at the document tree root (you're actually concerned with the component root, coming...) can be a default formatting component when the original URI translated document or a higher level dhandler is absent.
Component trees can be developed in parallel so that a sparse tree of components earlier in the component root path take precedence over those later in the path. We're currently planning on implementing developer-specific sparse trees so that developers can work in their own self-contained environment accessing a component root path specific to their access. Integrating this with CVS will make our engineering a truly multiuser development environment. This characteristic is unique to Mason (AFAIK) and one of the key advantages it maintains over other mod_perl component systems.