Pros
Working at MasterCard (Operations & Technologies Headquarters) is exciting due to the many opportunities that come about in a technology company. There are always changes to our infrastructure and we're constantly pushing the envelope with new and exciting adoption (or creation of) technologies. What I mean to say is that it is clear how many parts of the Technology Organization of MasterCard, in just a 2 year span, an Operations employee (Analyst through Sr. Professional) will have established a firm working knowledge of many different industry leading products, software or technology types that will decorate their resume beyond what many might achieve in their entire career.
Cons
The only 2 Cons I've heard around the office are really these: 1) Due to the high pressure demands for rapid development or fast turn around on various projects, many find themselves overwhelmed. It certainly isn't a workplace for the meek (though I personally enjoy the pressure, it drives me personally). 2) Appreciation is lacking for those that burst with initiative and improvement efforts that change the company for the good. I've been witness to several cases where an employee has improved a process or business practice that has caused a financial savings greater than that employee's salary (in a few cases these savings are realized annually).