Pros
DAI's mission - working on development projects in underdeveloped countries (mainly under USAID contracts) is interesting. The Bethesda headquarters office is nice. Benefits and vacation policies are good. Flexible workplace, they allow some telecommuting.
Cons
Sometimes it's hard to get things done due to an "over-collaborative" environment where it's unclear who the decision makers are, and much time is used to discuss issues with no clear results. People seem to waste a lot of time on unimportant issues. Bonuses for anyone below director level (i.e. the people who are doing the actual work to keep the place going) are too low & have no relationship to any objective measure of performance. They are too subjective, depending on who you work for.