Pros
Decent benefits and paid time off (except some areas have such high turnover and workload that taking time off is not possible)
Cons
See above; generally, if you work there for a while it’s out with the old and in with the new. There will always be a steady stream of candidates to fill any role given the name recognition even if you are breaking your back to get the work done. New hires treated with more respect (and higher pay) than those who have years (even decades) of institutional knowledge. Once you get in the system and been there several years, your pay will not keep up with the market. However, because the organization is so big, there is room to move around through the internal job posting & transfer system for better / different opportunities.