Pros
Amex is a world-class brand that gives gravitas to your resume once you've been there 2-3 years. There are numerous marketing and finance opportunities, including a few rotational programs that allow you to gain global knowledge and experience. Amex is great in terms of work-life balance: if you are sick, need to work from home or take time off personal/ family reasons, almost all bosses support that. Mid-year and annual reviews help track your progress and highlight your skills. If diversity is important to you - Amex has around 8 employee diversity networks that allow you to connect with others. It's also an extremely diverse population working at HQ. Grads recruited right out of school get access to employee development programs.
Kontras
The highly-matrixed nature of the organization and large number of team/ group projects results in little accountability at the top when things go south; also, a very large number of people will take credit for team project successes despite marginal contributions. If you have to pull long hours to cover an open position or deliver a new product, your compensation will fall in line with the department's average...this can be a disincentive for high-performers. Also, even if you have good ratings and performance, it can be hard to move upward outside of your immediate LOB if your managers are not the oriented to publicly praising their team's efforts or care little about the advancement of those under them. The pay for those with degrees is below-par for a Manhattan-headquartered marketing company with (until this quarter) healthy returns. Amex's NYC healthcare program (an HSA) also forces undue costs to individuals (save up early!). You can still live off of your salary if you're single...just not in Manhattan without serious, major, quality-of-life sacrifices.