Vantaggi
Stable working environment, good for those who likes to work in a very organisational environment, yet not a suitable place for those who would like to make a impact to human rights causes. In short, it is a good working environment for bureaucrats (yes... it is so big and that it developed a working culture very close to governments!), but not for real activists and NGO workers. Good work life balance for those who does not need to deal with ad hoc work, very tough working hours for those that needs to.
Svantaggi
Crazy politics both inter-departmental and intra-departmental, disrespectful for expertise, disrespect talents, does not value intelligence, little ownership of projects, whether you will actually enjoy your work heavily depends on your line manager, there are good line managers out there but they are not the majority.