Pros
Great culture. Highly driven. Encourages taking chances and innovating. Values speaking up and giving your honest opinion on decisions, not just being a "yes person". Super interesting problems to solve from an engineering point of view. Strong focus on quality code and engineering excellence. If you want an opportunity to really push yourself to the limits of your talents, this is the kind of place where that will be encouraged and rewarded.
Cons
Need to be able to handle a fast-paced, changing environment, which can be a blessing or a curse depending on your nature. Not an "easy" place to work, at least in terms of pace and achieving objectives. The culture is very positive, but also very ambitious, so there's always more to do than you can get done. Again, not a bad thing in my opinion, but it's certainly not for everybody. Best suited for people who want a lot of responsibility and an opportunity to grow fast.