What separates a good PMM from a great PMM?

A great product marketing manager is obsessive about their craft. They study product marketing. They watch how other companies execute their product marketing. They follow practitioners and strategists on Twitter. They read all the classic books on product marketing, product management and copywriting. They focus on being great for the sake of being great and delivering results, not to climb the career ladder. 

Great PMMs really understand the nuances behind messaging and are able to create simplicity out of complexity. 

They are framework-driven. 

They connect their work to strategic company initiatives, especially those tied to growth. 

They are "drivers" with a strong bias to action. 

They are phenomenal communicators and are able to hold their own in discussions and debates with senior leaders. 

They use the right mix of instinct and data to make decisions. 

They make others "want" to work with them on projects. 

Their work is memorable.