Ventajas
The smaller programs have a very family-like culture and everybody helps everybody. Management is generally approachable and transparent. Handling of the COVID situation was as on-point as can be expected for a company this large and with so much of its work requiring on-site presence. The benefits are solid; work hours are flexible and the vacation policy is better than most. The company will pay for continuing education with good grades and that is hard to beat.
Desventajas
A large organization like Lockheed has a lot of inertia and is very averse to spending resources on changing how a program is run until performance on that program starts overtly deteriorating. Sometimes there is more staff than work available and you will spend days to weeks doing odd jobs to fill your hours; times like those can be stressful.