Pros
There are some really great people to work with at the ISO. The building is very nice, and there are a lot of recreational activities on site. The ISO has a generous retirement plan for long timers, that if you manage to survive the biyearly "reorg." My interactions with my VP were always pleasant.
Cons
There are few toxic silos at the ISO. These silos are either maintained by Visa workers or by a continuous cycles of resignations and hiring, there is a position at the ISO that has not been closed for about two years now. The ISO abuse its Visa employees with high work load and lower salaries. If you're on Visa then please, for your dignity, look somewhere else before attempting the ISO. Many who receives their green card while working at the ISO leaves within few months. The phrase "The fish rots from the head" couldn't be more adequate to describe the culture problems that plauge certain business units. The place is extremely flat so the ambition and politics of the directors can burn down these business units while their directors are chasing glory. If you're in a diseased business units then there is a small chance of moving inside the ISO. A good test to figure out if the group that you're applying to is in a bad shape is to ask these two questions: how many of my future team mates have less than two years of experience? How many of my teammates are on Visa? Maybe HR should conduct the same test to see which groups are in awful shape. The ISO likes to advertise itself as a "competitive work environment" where pay is a measure of an employee contribution, but it is not. Merit increases are limited to 4%, rarely awarded, so starting salary is the most important factor in determining compensation. Raises are usually around 2%. There are many frustrated employees who are stuck because of a two year relocation contract.