I'm trying to run Catalyst on my ancient Red Hat webserver, and boy does that suck to install. It requires everything and the default scripts for installation just don't work out of the box.
I finally got it to work, and when it's clean I'll write it up.
As I'm cleaning it out though my main problem is mod_perl itself: When you load a module, it only get's loaded once - so if you have several apps and they, for convenience, maintain their old ancient "backwards compatible" versions of modules, with mod_perl you're sunk.
I would love to hear of any cures for this problem
Meanwhile, Catalyst itself is really easy to use. You write very little code and accomplish a great deal with the code.