Pros
An inspiring place to work, I really loved my coworkers, the product and felt like I was constantly learning new things. While I can only speak from experience regarding one department, they are pretty good about transitioning interns to full-time staff and moving hardworking low-level staff into better positions - there were a lot of long-time staff when I was there, which I generally take as a good sign in a company (means good pay and upward mobility).
Cons
I realized that I hate being in Admin, not necessarily because of the company but just that wasn't the right role for me. If another position had opened, I would have stayed but I'm much happier working on policy and program management. Also, my last year was NOT 2011, it was 2009 but that wasn't an option.