Pros
It used to be a meritocracy, driven by true rocket-scientist, with years of expertise, and who were excellent mentors. You could learn great amounts about the process of bias-free engineering processes, systems engineering at scale, and of course GN&C from the thought leaders in the field. Yes, there were roadblocks in terms of security firewalls, and DOD bureaucracy. But the sense of adventure and exploration made up for this.
Kontras
The past 5 years has seen things go down and down. Management clicks, micro-management by young managers who are have pet favorite technologies, who force decisions that have no bearing on customer, or the tech staff. Rather than individuals driving new directions, it is now a job-shop, you are assigned tasks, and pigeon-holed into work. Might be ok for an intern to pick up some skills, but don't make a career here anymore.