Pros
A good amount of the staff are good people with interesting backgrounds and are great to work with. Generally the working situation is flexible. The data is pretty interesting stuff.
Cons
There is no opportunity for advancement. Senior staff are solely concerned with their personal matters and pay little to no attention to anyone else. The organization as a whole has zero transparency as to decision making, with Director level staff often being blindsided by random decisions from on high. Junior staff may as well be interns. Ironically this makes it a great place to intern, as the pay is nearly as good as what they pay junior staff, and you get to do actual work, instead of the monotonous grunt work you find at other NGOs. However, this is not the place to launch a career. At best, you can work for a year and move on. If you stay longer than that you are damaging your professional prospects. I'm sure the leadership believes in their ideals, but they certainly never follow through on them. Nepotism is rather rampant, from the top down.