Pros
If you know what you're getting yourself in to (which you should, they're very transparent about it throughout the interview process and in online presence) then it's really a once-in-a-lifetime opportunity to build something from the ground up. If you're looking for a straight-path to a cushy life, this is NOT it. But if you're willing to take the jump from the corporate slug to something unpredictable, challenging, and rewarding, then there's no better place
Cons
Hours are long, but the work truly is never done. Almost everything that's being done has no precedence, so the lack of playbooks, frameworks, and structure is definitely a double-edged sword. Typical startup politics, nothing different than any corp job though High attrition, also not atypical for fast-growing startups, especially one with a more intense, traditional startup culture