One thing I'd like to say about using OO in Perl (or anywhere for that matter) is this:

Just as proper English spelling and grammar should be well-known to a native English speaker, I wouldn't expect an English speaker to apply them to every phrase spoken or typed. Just as one can easily distinguish between the words of someone who understands English grammar and one who does not, the software written by one who understands OO will often stand out from software written by one who has limited understanding of OO.

Once you know, you can spot the (albeit sometimes subtle) differences.