Pros
Reason why it's the #3 best agency in the world (at least according to AdAge 2018 rankings): the best leadership team of any advertising agency today - they truly have every next step outlined, they have vision and capacity to make it happen.
Great mentors/peer support system. Everyone has an amazing and "yes-and..." work ethic. Tremendous work-life balance. (Though we don't really talk about it but) Benefits are a great! Lastly, everyone is just down to earth, smart and genuinely nice people.
Intercompany transfers either domestically in the US or internationally are also options - provided you're a top performer, and have the desire to stay.
For internationals, VML will work with you - but you definitely need to stand out and be willing to demonstrate (above and beyond)
Bottom line: You could build a long-term career here and continuously be challenged and at the forefront of the industry; and have lifelong friends/family coming out of the experience.
Cons
Initial base compensation is relative to the living standards of where you join the company. So you will likely not maximize earning potential.