Pros
Best equipment available. Cool office design. Free drinks and snacks in the kitchen. Incredibly smart and motivated co-workers. Healthy mix of discipline and freedom in everyday work. Able to work remotely occasionally. Co-workers are very supportive from day one. Management is approachable. Organization changes constantly with new people coming in weekly. Constant change creates great new career opportunities. Management puts people first. Both employees and customers. Possibility to move between teams and projects easily. Technology stack is in many places cutting edge and exciting to work with. Exciting to see a company grow up. Stock options. Practicing Scrum. Specially retros which creates incredibly important feedback loop with co-workers. Company events are great in program and in location. Management is thinking long-term about company building. Management is pretty transparent and communicates plans, decisions and initiatives monthly.
Cons
Problems with scaling organization. Legacy code is limiting sometimes. Hard to keep track of all the new faces in the office. Not to say getting familiar with them. Office could have some minor details added to make it really great. Individual compensations could be better (sports, books, conferences etc). Communication between Tallinn & Menlo Park office difficult because of the timezone difference.