moof1138 has asked for the wisdom of the Perl Monks concerning the following question:
I do a fair amount of Perl work in a lot of domains, but for web stuff things fall roughly into two classes: fairly simple template based DB driven web apps that run on mod_perl, and use CGI.pm to get params/cookies/etc., set headers/cookies/etc, and return the HTML. Then there are generally simpler tools that handle XMLHttpRequest again using CGI.pm to get params/cookies/etc. and return results in JSON. We use a lot of our own modules (along with blessed, lovely CPAN) to handle keeping things fairly cleanly separated into their proper domains, and adhere to MVC, so the actual cgi bits are pretty small and simple. (Side note - Catalyst seemed a bit heavy weight to me in the past, but I've been working on making some new things in Catalyst, since I see it it can take some of the work off our hands, and it seems like there really is some gain there.)
Things currently work well, are easy to read, and are easy to maintain. I've been reading posts from folks on various sites discussing how great Plack is off and on for a while now, so I've been looking into it. I looked over the PSGI FAQ which took a crack at explaining this very question, and I think that since we only have a few folks in our org who work on these things, they are never going open source, and will always be able to run on servers we control, that Plack it not really something I need to worry about for my current purposes (which obviously might change if deployment goals change), but I wanted to just throw it out there to see if there was some benefit for my current kind of deployment I might be missing.