Pros
Proof is a truly unique place to work. Everyone here is so positive, enthusiastic, creative, smart, and talented. It really feels like we are all here doing "the work of our lives". We have a great mission to make the internet a more honest place that inspires me to do great work. The work life balance is real, we get all the standard startup perks (snacks, work from home, etc), and people hang out outside of work a lot because of real friendships. Overall, I feel so proud to work here and am so excited about the problems we're solving and the huge impact we're making on the world.
Cons
It's a startup so things move quickly. If you're not used to that or willing to work hard and not have stuff handed to you, it will be a tough place to be. To thrive, you have to be self motivated to figure out and own problems. For the right person, I think that's attractive, but it can be tough at times.