Pros
Every chart associated with the company is a hockey stick. Every executive, manager, and leader in the company is down-to-earth. Solving big problems at big scales, surrounded by the top engineers, product managers, sales, customer success, etc people in Boston. Every employee is highly motivated, it's unlike anything I have seen in my career. At 200+ employees, everyone is focused on the goals of the company. There is one team, team Localytics. I know this review sounds overly positive, but it is truly a remarkable time to be here.
Cons
Everything is moving at an incredible speed, you must be comfortable with ambiguity and sometimes foregoing a seatbelt. Things change fast, and you have to be able to react. This is not necessarily a con, but it's not a place for everyone -- if you cannot turn on a dime if the situation requires it, you may find yourself lost.