This module absolutely flies. I'd previously been using MooseX::Method::Signatures and converted my code to use Method::Signatures. This module brings a level of elegance that Perl 5 methods are missing with absolutely no performance penalty. My benchmarks show it about the same speed as just using subs and 100 times faster than MooseX::Method::Signatures.
This module helps surviving in a multi-language work environment where you need to participate in the discussion about the typical Perl FUD. And, admittedly, it really adds even more beauty and readability to your code.
I used it in the context of a Moose'ified and RPC:XML::Server-based application, providing an IMHO sufficiently complex environment of subs and methods that finally gave me a good feeling about this module, not being that alpha grade as it calls itself.
I would, of course, really appreciate it if the trailing semicolon after a method can be avoided. But currently the advantages in readability are worth it.