Pros
Fun people and lots of opportunities to grow your career and take on new challenges- as long as you aren't trying to do technical work. It's a great place to start if you are really early in your career- or to come to if you are very senior, but it's a hard place to start in as a mid-career professional.
Cons
Unfortunately, "opportunities" are usually chances to work lots of overtime for no extra pay. Even the best opportunities don't give HQ staff the opportunity to get involved in any of the technical work. HQ staff are there to manage the contract and be administrators. Work life balance is terrible. Everyone talks about it but there doesn't seem to be a real inclination to change it. Senior mangement talks a lot about being mission driven, but the mission seems to be winning new projects and making money- not that they aren't doing some good work, but this place is a profit center for sure.