It is a small company where there isn't a lot of runway to be a button-pusher. You will need to think critically about what you do and constantly try to improve.
It's also not a culture of unconditional positivity, which can be a con if you are the type of person that does not do well in "tell-it-like-it-is" environments. Everything is up for debate/criticism, which can be both amazing and crippling.
They have had problems with lack of people management and communication kind of stuff in the past. The values and bones of the culture are really good, but they aren't good at doing it deliberately yet.