Overloads are good when they make sense. For instance, DateTime overloads subtraction (which results in a DateTime::Duration object) and comparison. DateTime::Duration overloads addition, subtraction, and comparison. These make sense and are terribly convenient. It is obvious from looking at the code what they do.

Sometimes it's not so obvious, though. For instance...

fetch("google.com") > my $content;

What is being compared? Length? Recency? (How does it know the date of the content in the scalar? Or does $content have to be another item fetched with the same module?) It's not at all obvious from reading the code. From a perspective of maintainability, I would consider that to be not such a good use of overloading.