Pros
Truly a place where you can have autonomy, ownership and you can run with things without having everyone micromanage you every step of the way. There is high trust and there is safety if something doesn't work out immediately, for you to go and own up to mistakes and turn them into learnings. The high level of ownership is not for everyone, with trust comes visibility. I personally think this is great, but you have to be aware of this coming in so you know if this is right for you. It is also a place with a team that welcomes you warmly and makes you feel like part of the fabric of the team from the get-go.
Cons
Growing pains of any startup. You have to be ready for the pace and dedication it requires. Onboarding in general is good, but you definitely have to take ownership over your own learning - especially anything more technical. The team are there to support you, but help yourself first and then you can take less of their time.