Pros
A permeating sense of moral purpose, without compromising the intellectual integrity of the work.
A great bunch of people, who are fun to be with in the office, and outside of it - on the occasions that that is possible.
Everyone here is talented and experienced, and you will learn a lot, no matter how extensive your past experience.
The compensation structure, due to the nature of the work and low cost of living, makes it very competitive.
Cons
Long hours and distant locations - it gets wearing living in the dust for such long stretches.
You're surrounded by poverty quite often, and it's hard to resist becoming either demoralized or desensitized.