Pros
They give Very high pay compared to the rest of industry and they are involved in some interesting work with interesting customers. It is a good place for young engineers to gain 5 years of experience.
Cons
The defense industry is undergoing a pullback and NG is shrinking faster than management can handle so layoffs are common. There is also a significant trend toward laying off older engineers (50+). They get away with it by also laying off token younger engineeers to make it look fair but the real goal is to get rid of high salaries and older people. Also, once an engineer reachs about 10 or 15 years of experience there is no where to go for career growth. Promotions are almost non-existent once an engineer has 15 years or so of experience. It is also common to receive a yearly review that does not match the employee's contribution. You can walk on water and turn it into wine and still get a below average review if you are not one of the chosen ones who rubs shoudlers with the right people.