Pros
Remote position. Great local management. Lots of resources to get what you need done, even being remote. Lots of upside for $ and career growth if you work hard and make the right connections internally. Positive, good and (some) smart people whom you can learn a lot from. Excellent work-life balance. Good benefits. The company takes care of you. Great brand to represent and to have on your resume. Brand makes accessing customers and targets simple. All local reps in your market from other companies will want to work with you and "leverage" the power of the Amex brand, so makes networking easy.
Kontras
Lagging a bit in technology and in the payments industry. Typical, large company mentality....slow moving, almost 60K employees so to be expected. Being successful at Amex is all about putting yourself out there - getting your results and yourself noticed so you can build your own brand internally (not really a con, just good to know what you're getting into).