What is your opinion on “role over company” vs “any seat on a rocketship” for a PMM early in their career?

I can tell you based on quite a bit of experience that this is the easiest question I'll ever answer on the topic of building a successful PMM career. It isn't even close. When you are early on in your career, forget about the role, title, pay, etc. Instead, jump into any seat on a rocketship. 

When you are on a rocketship, if you perform well, there will be plenty of opportunities for growth as the company grows, and the experience you gain will be highly valued by other companies hoping to achieve similar growth. 

I know it can be hard to see this when you are early on in your career, but in hindsight it will be clear as day.

Strong preference toward "any seat on a rocketship". It's much better to join a strong company, in any role, then to take a role in a company that's going into a ditch. All that said, identifying the best companies vs. the ditch-bound is challenging, especially for a startup company and extra-especially if you are early in your career.

Early in your career, I'd totally go for the rocketship option to be honest.

Best way to learn a lot all the facets of GTM, get your hands dirty, influence key strategic initiatives, show impact, etc. - that'll follow you for the rest of your career!

Moving fast is the best way to learn fast, I'd say.