Pros
The people at this company are simultaneously the smartest and most humble group I've had the pleasure of working with. We're tackling a very difficult problem and the sense of unity and teamwork within the company is incredible. There's a lot of hard work to do, but it feels like we're all in it together. If you're a high performer who likes a challenge and working on something that has a very real impact on society this is a great place to be.
Cons
There's a lot of change happening and we're moving very quickly, so that leads to miscommunications at times. Since the company is so new we're often in uncharted territory and the exec team has to react. Sometimes that means we don't get much of a heads up, but, I also think this is pretty typical for a startup (this is my 3rd).