Pros
There is a strong engineering and company culture of building great products which influences practically all aspects of the job in a good way. There is a wide variety in the engineering problems we solve with opportunity to work across disciplines. The majority of engineers are very solid, love what they are doing, and are great to work with. There is very little management with an emphasis on individual technical ownership and decision making. If you have the potential, the sky is the limit in terms of product impact and technical ownership.
Cons
It is a rapidly growing startup and often not everything is always perfectly planned or communicated so you have to be comfortable with some level ambiguity and taking initiative to get things done.