Pros
My very first real job experience, it feels like you are given space to try, fail and improve. The environment is informal and fun. Colleagues are from many different countries and generally in their late twenties. The daily activities and long term goals help improve society. Access to high-level European Institutions and Organisations, gives an insight of how EU policy works. Managers are ok with mistakes, which I appreciate.
Cons
Challenging to work together with people from all over the world, in offices overseas and managing global activities in more than one language. Different projects have very different expectations and scale, can be hard to juggle. Young people are given a very high level of responsibility and trust almost immediately, I would advise it if you are already a structured and proactive person. The management style is quite flat, not much hierarchy.