Pros
Great mission, good colleagues trying to get stuff done, excellent training and links to connect with colleagues in other countries, Great frontline humanitarian impact with opportunities for any staff member to get directly involved
Cons
Mountains upon mountains of paperwork for even the smallest action and decision. 50 - 70 % of EVERYONE'S time is spent writing memos (famously called NFRs), reports, memos to explain why another memo is required. Any kind of paper work you could imagine? WFP has it and has a report and manual about it. And this is just for basic work actions like ordering supplies, requesting travel, organising a meeting or workshop. Should you actually wish to innovate or change a process...Good luck. This is only done at HQ (Rome). Everyone else's job is to comply. Also famously the worst paying agency of the UN. What is done by an assistant or associate at WFP would be graded Officer level responsibility at other UN agencies.