Pros
Pew has an enormous wealth of money, meaning that campaigns have the ability to spend money to achieve results that for many non-profits is their entire operational budget. For many who have worked in nonprofit sectors before, the looming threat of finances always damages campaigns, but you will not find that at Pew.
Cons
You cannot receive any form of promotion until you have been at Pew over two years. After that you cannot receive a second promotion for another three years. Please note it is extremely difficult to even receive a promotion due to Human Resources extremely lengthy rules and organization charts. If you are international, do not even think of applying to any US based jobs- Pew does not issue work visas. It is so narrow-minded as an institution that it believes all of it talent should be from the United States. In 1950s perhaps this would be tolerated but this jingo-centric view has no place in the 21st century.