Vantaggi
The direct monetary benefits are great: my salary is far higher than it would be just about anywhere else, and there's a pension, 401k, pretty good health insurance with a free $1500 to cover deductibles. When/if they decide to relocate you, their relocation package is top-notch, too. Performance expectations are pretty minimal; so if you're lazy or just have a bad month, you have nothing to worry about.
Svantaggi
Typical of risk-averse huge companies, they never fire anyone. So there are a lot of people who shouldn't be there. Don't expect to be surrounded by star performers and brilliant minds. Some of their tech stack (okay, a lot of it) is ancient and they have some pretty bad practices some places. They're currently going through a huge reorg company-wide. This is going to lead to huge instability -- they are forcibly relocating whole teams, and people don't want to leave, which means whole teams will have brand new staff. Nothing will get done in many places for several years while they close the knowledge gap. When performance reviews come around, basically "everyone gets a 2" which is "average". Literally one person on a team may get a single "3", which is as high as you get get. Almost no one gets a "1", regardless if many should. So this means you probably won't get rewarded specifically for performing well unless your manager happens to really like you.