Pros
Organization is focused on a great mission. Employees are provided with excellent benefits including plenty of paid time off, 401(k) matching, pretty good insurance, etc. There is a fair amount of autonomy in the positions.
Cons
Upper and middle management have no real background in business, which is required at an organization of this size. This causes problems all over including poor focus on core areas, ignoring growing problems, etc. As others have said, there is a huge disconnect from those positions and more entry level staff. The largest issue is a complete lack of career advancement opportunities. You will not get promoted unless you fight tooth and nail for it, and even then it will take years. Managers often do not think about the needs of their employees and are only looking for performance metrics.