Pros
There is so much to explore and be done across all projects and teams. Between scaling and the sheer complexity of the problems their tackling - you will never be bored. The team also has a wide range of backgrounds, with some many who have a more laid back attitude than most start-ups this size. Not sure if it's because all the founders have been at various companies and jobs before - but it's a nice stable change from other startups I've worked at. And everyone is so passionate and hard working - it makes you super inspired to get up every day to go to work.
Cons
It's a growing start up so there's always more to do than people to do it. If 9-5 is your jam, not sure this is the place - thought they are pretty flexible with letting folks do their work when and where they need to (there are a surprising number of parents here).