Pros
Who can argue with a 35 hour work week, a great mission statement and membership base, and some great benefits. They provide alot of training to their employees throughout the year, which helps you network with other employees. It's located near the metro, plus they have flexible work hours. It has to be one of the better places I have worked at but lack of job opportunities/challenges will make you consider trading all those pros.
Kontras
I would say opportunities for advancement are slim. So make sure you are happy with the job you're applying for because there will be an internal line to get behind for any job openings that occur. So units have been under constant reorg so you will find some stressed out individauls. It's located right in DC, which can be great for lunch variety but they hire from DC pool of talent so it's sort of like Metro :( at times.