Pros
Low stress, easy to maintain a good life-work balance. GDLS is a placed you go to collect a good paycheck and raise a family.
Cons
I worked there for 10+ years and left to acquire new skills and continue my professional growth. The company culture is improving but still pretty down. Department heads focus on empire building and push bloat into contract bids to maintain them. Nepotism is rampant, they only hire management from within and all managers are afraid to shake the boat. Their engineering design practices and processes, especially for Abrams is really behind. At the time I left 40% of their manhours were funded by Abrams Sustainment and they've been handed this chunk of money for 25+ years; it is a fine example of corporate welfare in the defense industry. At this point they are probably too large to fail, but I really hope other competitors (Oshkosh, Rheinmetall, etc) contain to take business away.