Pros
Rapid growth--Major plans & ambitions for expansion into different regions and product lines, at the same time. Not just talk, you see it actually happening, fast. Lots to do. Very cool collogues and a youthful vibe. Still small--You'll get to speak to the top executives and they'll know your name. Your email will be just your first name @cozey :)
Cons
Interview process does take a long time. The COO since told me directly they are very careful with hiring and that he does not want to lay anyone off, ever. That's at least a respectable reason especially these days. At the time though it felt like it was taking forever. Later stage, but still a startup; a bit chaotic. Managers are busy, structure can be loose and there'll be times you need to seek out tasks that need doing, which can feel uncomfortable.