As perl was (imho) never a programming language with the focus for webapps, I'd just kind of wipe it out of this comparison and stick to php vs. ruby (on rails), as both of them had the webapp stuff as focus.
Perl is pretty awesome but from my personal experience it makes some things harder to implement (at least for me) as it would do with php.
Maybe the more you discuss this tomic, the more dogmatic / philosophic it will get
So with a concrete goal of what do develop you might get more helpfull answers. But just to have an idea maybe something like this can help you a bit more: