Pros
It is more in the name. The United Nations is a global network, and with many country offices world wide, one gets to connect and coordinate with many international colleagues and attend online events.
Cons
The issue with every UN office is that although they boast of being "inclusive" and "global," there is zero sense of team spirit! Each person is either trying to outdo or outsmart the other. The constant leg-pulling is extremely demoralizing and toxic. With outdated policies and systems, unlike other donor agencies, the work culture feels rigid and unaccepting of new concepts or ideas. They want to stick to the old-school ideas of running an office. Another major red flag of the work culture here is the general lack of acceptance of new staff, particularly someone not from a UN background; the organization is extremely biased towards volunteers (UNVs), not because of the quality of their work but because they work for practically no pay! Anyone with a different concept is made a mockery of. So all those who are thinking of joining the UN to "change the world", join the long line of nepotism and red-tapism, which will literally drain you of any enthusiasm you have by the time you get in, if you do that is!