Fulfilling work and inspiring mission - you feel like you're contributing to a worthy cause. A great team of fellow workers who really care and have a work hard/play hard attitiude. The senior management are committed to ethical, sustainable development initiatives and are willing to listen to input and feedback from employees throughout the company.
Cons
Balancing work volume with time is tough, and positions tend to evolve over time without much formal explanation of changing responsibilities. Expectations are high and the job can take over your life. Limited growth potential due to small company.