Pros
Amex people tend to be highly collaborative, intelligent and motivated. Feels good to work for a brand that does cool stuff and is respected. Flexible work arrangements are amazing and 20 week paternity leave at full pay for fathers is practically unheard of elsewhere (26 weeks for mothers). Amex has gotten quite good at product management (not the case 3 years ago) so if you are interested in product, you can learn a lot here.
Cons
When amex lost the Costco partnerships the company had to tighten its belt significantly or fail and famously cut $1 billion of cost. While I’ve noticed some nice things slowly coming back (like being able to fly business class on longer work flights), some frustrating stuff like overcrowded open floors, not always having a permanent desk, and - seriously - not enough trash cans, don’t make you feel like everything is being done to make you comfortable. Some teams also are not particularly agile so getting things done isn’t always super speedy. If you like the freedom of working at a small entrepreneurial company where you can pretty much do anything, this is not a place for you.