Pros
The founders (Drew and Arash) are very accessible and highly engaged in the day to day operations of the company - as someone else pointed out, they definitely "walk the walk". One of the biggest benefits i've experienced has been the people - you truly get to work with insanely smart, talented people who are genuinely fun to work with - and this is the result of an intense hiring process that screens out a lot of great candidates. Office perks in SF are fantastic (particularly the world class food) and they're getting better at the remote offices. (Side note about remote offices - they are treated with the same level of importance as the SF office, we get tons of visitors, and people in SF make a point of keeping us informed about what's going on.) Compensation is generally in line with similar positions in the market, depending on role. The company is growing quickly (but responsibly), so there is ample opportunity to grow as new teams are being formed regularly.
Cons
The San Francisco office is a bit crowded right now due to rapid growth and the open seating plan; this can make it difficult (but not impossible) to focus on work. Although decisions at the founder level are very transparent to the whole company, some teams don't enjoy the same level of transparency from middle-management. Career path options haven't historically been very transparent, but that's been improving thanks to a massive recent push to improve learning and development.