Pros
Mercy Corps is truly powered by social innovation. The organization is chock-full of not only top-notch thinkers, but also smart, experienced program staff, "doers" and implementers. Staff is given the chance to suggest and pilot new approaches; risk is encouraged. Programs develop and scale up quickly, and the organization learns from both successes and failures. In addition, the marketing and communications teams are given the latitude and autonomy to move quickly, giving the organization the chance to raise money quickly and get it where the needs are greatest.
Cons
Unless you're on the "leadership track" (whether at headquarters or in the field), there are few chances for real advancement. If you've been with the organization a while and are in line for a promotion, expect to have the word "Senior" placed before your current title and a bit more salary, but not much more in terms of real power and influence. When this happens, people leave, taking much organizational knowledge and know-how with them. Leadership can be clique-y. High-level processes are often not as transparent as they can be. Things can stagnate at the executive level, stymieing what could otherwise be an even more creative, effective organization.