Pros
Incredible coworkers, many of whom who have been involved in open sourced software for years and are really committed to solving problems in creative ways. Fun to get to know coworkers and users all across the globe. A strong, if still small, design organization and strong support for design from most key stakeholders. I have also seen everyone at the company make real efforts to be inclusive in hiring, management, and working practices.
Cons
Regular struggles of a startup like ambiguity about priorities and roles/responsibilities because of rapid growth and many of us are wearing several hats, though I think our challenges are milder than most startups from what I've heard. I've been able to keep a good work-life balance, take vacations.