Pros
Awesome team of intelligent and innovative individuals. Great opportunity to make a huge impact on the industry. One of the few startups that are doing well which will get you a lot of recognition. Good work/life balance with a lot of flexibility and autonomy.
Cons
MongoDB is experiencing some growing pains right now with a lot of bureaucratic policies being put in place partially due to new execs. It's normal to have more structure as the team gets bigger but the way in which it is implemented could be handled a bit better. Fast pace growth but sometimes culture fit is sacrificed in the process. Healthy compensation packages for newcomers but, no incentives are given to existing employees who have been with the company. New managers also needs more training.