Pros
MongoDB has grown rapidly over the five years I've worked here, both in staff numbers and in the maturity of the product offering. Likewise I seen many people start their careers and use MongoDB as a launchpad for their own growth. The company culture is supportive and encourages introspection backed by a transparent, open executive team. MongoDB's products have global reach and help manage data for many of the world's most dynamic companies, so there are plenty of opportunities to have impact by adding features, improving quality or making products easier to use.
Cons
Head office is in New York, which is a long way from Sydney. Some roles involve moderate amounts of travel, which is either a pro or a con depending on your point of view. Likewise for morning meetings.