Pros
The growth and learning here are the real deal. You're handed real ownership early. Smart people to learn from, short path from idea to shipping, and a mission you can actually believe in. If you want to be challenged and stretch quickly, it's a great place to be at.
Cons
It moves fast, and that's a double-edged sword. Priorities can shift before you've finished what you started, and process/tooling sometimes lags behind how quickly the company is scaling. You have to be comfortable with ambiguity and willing to fill gaps yourself - people who need everything clearly defined up front may find it frustrating. The pace can blur the line between "energizing" and "a lot."