Avantages
Great pay, lots of different groups doing many diverse things. Hours were flexible, and a lot of very smart people work there. There were even separate technical and management career paths to choose from.
Inconvénients
Since they're a government contractor, mediocrity rules. The emphasis is on spending as much time and money as possible, since what you're selling is hours, not product. That also leads to staff bloating, where it's better to have three people do the job of one wherever possible. Management can also be clueless. They have the attitude that a manager doesn't have to know anything about the department they're managing so long as they can look good in front of a PowerPoint presentation. They used to be very innovative, but now they sub out almost all of the innovation, and just do the project management.