Pros
Incedibly diverse opportunities for engineers, from plant operations to manufacturing, ship and submarine design, testing, nuclear power, R&D, and more. There is something for anyone having the energy and fortitude to excel in their current tasks and reach for that next thing. There are few things as satisfying as seeing the enormous aircraft carrier or submarine that you helped create sail off to help and protect our country.
Cons
The core business is government (Navy) contracting which is good for many things (stability, diverse and technically challenging work, among others), but it also brings heavy layers of bureaucracy. This is tends to drive business model toward innate sluggishness and inefficiency which can sometimes be frustrating to hard charging employees. However, I have found, from over 30 years of employment, that there is plenty of opportunities to stay engaged and be sufficiently rewarded.