Pros
You will get incredible hands-on opportunities, be able to design and manage projects, and have the opportunity to travel to some incredible places. If you do a good job, you'll have a real shot at enabling communities to access the information they need to break out of poverty. You'll be able to drive long-term strategy for the organization if you have solid ideas and go after them (as well as the funding for them).
Cons
There are few policies in place, and you will lack the kind of support from a larger firm. You will do a lot of fundraising and proposal development.