Moose is great, but it does introduce a slight performance hit to your code. In the more than 15 years since it was first released, hardware improvements have made this less of a problem than it once was. Even so, if performance is a concern for your project, Moose might not be what you want. It also has a fairly big collection of non-core dependencies.

Moo is a lighter weight version, minus with meta-object protocol, but supporting nearly all of Moose's other features. It loads faster, sometimes runs faster, and has fewer dependencies. (And most of the dependencies it does have are just modules which used to be part of Moo but were split out into separate distributions.)

But what if you could have fast Moose-like object-oriented code without the dependencies?

In 2013, Michael Schwern started work on Mite to do just that. It was abandoned in 2014, but I've taken it over and expanded the feature set to roughly equivalent to Moo.

Mite is an object-oriented programming compiler for Perl. It allows you to write familiar Moose-like object-oriented code, then compile that into plain Perl with zero non-core dependencies. Your compiled code does not even have a dependency on Mite itself!