Pros
Ancestry's mission is fantastic and there are so many wonderful, committed, excellent people that work there. There is generally a good work life balance and good atmosphere.
Cons
Ancestry keeps making the exact same mistakes. Ownership changes hands to new owners who then proceed to make mistakes which are almost identical to those of the previous owners. Ancestry just let go of two of their most critical and engaged product leaders, people almost universally valued and beloved, so that it can "can innovate" more quickly. On the other hand, parts of the company that are almost universally understood as serious issues are given more resources and authority while continuing to be equally ineffective. Steer clear of this company for now. The possibilities of the mission will only serve to frustrate you when you see how inept the leadership is when it comes to actually executing on it.