I like the fact that the authors regard pulling together chunks of CPAN with custom code to be a middle ground between "buy or build".

While installing N distributions from CPAN for large values of N can be annoying, I think the way CPAN hangs together tends to lead to more granular releases of software which enables this sort of thing to a greater extent than I've seen on other projects - I'll happily reach for a CPAN module rather than writing a dozen lines of code.