Pros
The institution is very small, around 200 people. Everyone knows everyone and they work in a pretty friendly manner. If you are competent, everyone will know very quickly. If you are incompetent, the same. Good budget for training, if you want to learn new skills, its covered by the ESM, up to a limit, but certainly several thousands of Euros a year per employee. No bad politics between the staff, they work well together, real teamwork. Staff supports each other, not only because they are smart and nice, but they all have two common enemies: highly incompetent HR and self serving and self centred senior management, obsessed with own personal image.
Cons
Senior management does not care about the staff, about work, creating value or doing anything good for EU, they only care about having an army of people preparing speeches and presentations that allows the senior management to shine. its like a PR agency. The ESM has become a highly useless and ghost institution since the last loan they gave to Greece. There is nothing to do there now, yet, they keep this institution running mainly to protect some highly paid board members that do nothing all day. They have all become highly irrelevant, just as the institution. Most people do reporting, internal briefings , minutes... Nothing of value or impact.