Pros
Amex has a good employee culture overall and can be a great school at the onset of one's career. Because of its size there are a lot of opportunities to do new things, acquire new skills, work abroad and build an exciting career. For those of us who spent most of our adult life there is was our second home and family. And in many ways Amex encouraged strong team spirit and inspired loyalty. Also it still has a good product and brand which make employees feel proud to work there and create opportunities to get good jobs after they leave.
Cons
Unfortunately in the past few years Amex lost its way. On one hand it hasn't been able to innovate enough and stay current while the market pressures are making it very difficult to maintain its current position. On the other, the formerly great employee culture has eroded in several areas turning to extremely competitive, over-pressuring and unforgiving. Moreover Amex is the classic example of promoting undeserving people simply for managing up well. Networking and presenting well is a lot more important than actually doing good work.