I use this module very often, it provides easy local development (combined with CGI::Application::Server) and installation under mod_perl as it provides a mod_perl handler interface, and as a CGI.pm user, it can be easily used with FastCCGI, or as a regular CGI script. My only complaints are that CGI::Application::Dispatch and CGI::Application::Dispatch::Regex can't be easily combined in the same package, and that CGI::Application::Dispatch::Regex hasn't been updated to support named regex captures, which would remove the need for the names parameter in the dispatch table (at least for Perl 5.10).
The previous reviewer just about got it right in my opinion. This is one of the best things about CGI::Application as far as I am concerned.
One gem that is worth mentioning is the "wildcard" rule and that use can rename the parameter that matches the wildcard. This is I feel very useful for building rules that handle multiple web pages.