Isn't perlbug just for core? rt.cpan.org is for cpan.
Personally, I like RT a lot (although I don't like installing it). Yes, logging in is a bit silly, when you follow a 'report a bug' link from cpan, you end up logged in to rt as 'anonymous', but then if you log out, and your browser remembers your authentication info, you can find yourself back at the correct queue pretty quickly.
Possibly the best thing about RT is that you don't have to log into it. You can get most of the benefits of RT by using the email interface.