ActiveState and Strawberry Perl take two different approaches to same problem: Windows does not have a C compiler (and make tool) that is part of the OS distribution like Linux operating systems do.
ActiveState takes the approach of using repositories of prebuilt/precompiled modules. The advantage of that approach is the end user does not need to worry about setting up a C compiler and that if there's a module available in a PPM repository, you're almost guaranteed that it will install without any issues. Unfortunately, you might also notice that in many cases the version of modules in the repository are older than the latest version available from CPAN. So if you're using ActiveState's ActivePerl, it's in your best interest to check PPM repositories for a desired module first and then install from CPAN only if you can't find it in a PPM repository.
Strawberry Perl takes another approach. They bundle all of the necessary tools needed to directly install modules from CPAN. The idea is that if you're used to installing modules in Linux, then you can do the same thing on Windows with Strawberry Perl. However, you don't have the level of guarantee of successful module install like you do with PPM repositories for ActivePerl. Although Strawberry Perl does have a ppm utility, I personally have never used it myself.