Pros
The best things about working at the IDB are: The interesting travel and projects you might be working on. If you are a project manager you will be an expert in some particular area of developmental finance, like transportation, for example. You will travel all over Latin America and the Caribbean advising governments on their transportation networks and making large loans to them. However, if you do not have a line job, that is a job working on projects, you may well have a very boring staff job in HR or project evaluation or coordinating with other developmental organizations that are do nothing jobs that are very difficult to escape from. Job security is great. For some reason it is very hard to fire someone, though if you are a complete loser they will eventually find a way. Salary and benefits are good. Health insurance is excellent. And for non-U.S. citizens the fact that you can move to Washington and have babies that are U.S. citizens is a great advantage.
Cons
Most positions above project manager are political. You will need a mentor to advise you on how to get ahead. Some positions are reserved for persons of specific large member country like Brasil or Mexico or the U.S. Also, there is a good deal of subtle corruption going on. The President will always put his friends in the senior positions regardless of their qualifications and will always try to buy the next election for President by doing this and by pressuring staff to be nice to the countries whose votes he needs. And this corruption trickles down and pollutes the whole organization with many staff members doing whatever their managers want them to even if it works against the goal of helping countries to develop. It is an extremely wasteful and inefficient anti-meritocracy. Finally, it is very hard to leave the IDB once it sucks you in. Some are ruined for life by the lack of accountability that characterizes the organization and many private sector companies know this and don't recruit from the IDB.