Pros
It's very dynamic. People are interesting, engaged, and enthusiastic. There are good training opportunities. For regional employees, there are a lot of opportunities for travel and expanding into different areas. I find senior management largely accessible and down-to-earth. It's in a convenient downtown location with modern, bright offices.
Cons
A lot of international development professionals leave because they're frustrated--too much admin, too much of an emphasis on proposal work, and not enough on project management (from the home office). As many others have said, the expectation is high for working long hours--and often erratic hours. Some of that is due to USAID deadlines and the nature of proposal work--but a lot of it has been due to poor allocation of resources and the bidding policy of going for nearly everything (to be fair, I think they are a bit more relaxed about this lately). Despite the fact that the people are mostly great, there are cliques and there is backbiting--and it's not discouraged.