Pros
Small enough for someone to still have a meaningful impact on the company. Everybody has direct access to the co-founders who are willing to listen to their employees ideas. Unusual to have two leaders of a company that are both crazy smart AND nice guys. Fun atmosphere - open floor plan surrounded by Star Wars posters and life size cutouts ranging from Tom Brady to Princess Leia. Free lunch catered every day. Health insurance and 401k were recently added.
Cons
Decision making / changes may be made too fast for some but that is typical for a mature startup. The technology is still a work in progress but was improving every day when I left. Customer service was also being greatly improved when I left. Heavily lopped sided to males vs. females but they were working on changing that too. My passion is not ad tech or I would still be there today.