Pros
It's a very fast-paced environment, there are always new ideas, projects, initiatives to work on. My job changes fairly quickly- it's dictated by what programs need to be started or focused on at the time and I love that (but I know it's not for everyone.) They let you run with ideas if you prove value to the customers. The customer obsession is real. If you thrive on that service mindset, it's THE place to work. They live and breath the core values, it's not just lip service. The people are great- it tends to attract people who have high intellect but even higher passion and that's infectious to be around.
Cons
The pace can run you in to the ground if you don't set (and stick to) boundaries. It's hard to ramp up and navigate because it's a massive organization that has tons of disparate teams and processes. They claim the "start-up mentality" and in some ways it's true, but not for the best. There's not a lot of rigor around processes and since everything is always changing there is an issue with gaining efficiency and knowledge sharing.