Great points Julia

I would agree that if you're already up to speed with an applicable skill set and have the talent to get the projects done, then marketing would make the most sense initially.
I'm *still* learning new skills, even after 2.5 years - and always will be

If I waited until I tested out of every single possible new exam and certification before moving forward I'd be pretty darn stuck. (And personally, I go for the learning for the sake of itself, not for the certs, but I do understand why some people work toward those - they certainly can't hurt!)
By the way, I especially liked and the phrase:
"Credentialitis is a terrible disease these days" Well said