Well, here's another non-Moose data point. We don't use it and probably never will. What I like about the current Perl approach to objects is that it is thin. It provides a layer of insulation to consumers of your objects without getting in the way of finding a best implementation internally to the object and without adding a lot of overhead.

That isn't to say we don't use formal OOP when the situation warrants it, but for systems that are that large and complex (loads of subclasses, co-varying types, etc), we use Java (gasp!), since the strict typing and compiler do a great job of inferring the correctness of code built around complex type systems. IMHO, any system complicated enough to justify the complexity of Moose needs something more robust and inferential than Moose.

Best, beth