Pros
American Express has very strong values as a company, and it's employees are very dedicated to the vision. As a current employee, I value my management team's commitment to my professional growth and work / life balance. I have been with the company for five years and have been given several opportunities to diversify my skill sets, including specializing in marketing analysis, working overseas to gain international experience (via the 6 month Global Rotation program), doing customer marketing and product marketing. I enjoy working alongside my coworkers and believe that I work amongst the best and brightest in the industry.
Kontras
The leadership at American Express is sometimes varied. The company allows you to change jobs every 18 months, and this is very much the culture here. People don't stay in their jobs long enough to make a meaningful impact. This also gives employees the false impression that they have the experience they need to move to Senior Management, just because they've been in 3-4 positions within just a few years. Also, the pay at American Express seems to be below industry standards and is a common complaint amongst coworkers. However I believe the people and the positive work environment may be worth the 10-20% lower pay, as compared to other financial service institutions.