I have used awstats in the past, and about to start using it again for some projects I am working on at the moment (logging normal web traffic as well as streaming media).
In the past I have never had any problems with it, and I know that several large ISPs that I have worked for in the past use it. Also it is written in Perl, which was a requirement you mentioned in your post.
Martin
Comment on Re^3: Scalable Perl Webalizer Alternative(s)