Vantaggi
The goals that this company has can't be matched. I could never walk away from the opportunity to be a part of that without regretting it later. The people that I work with are very talented and motivated. I would not devote myself to something that my peers don't care about. Additionally, most of my close friends are people that I work with. You learn by necessity, not by formal training. Many people complain about this but there is no replacement for experience and motive force to drive improvement. Some people complain about the compensation but I honestly think it is fair. I'm not wealthy but I also don't worry about money. Stock options are undervalued by most people.
Svantaggi
If you are in a role that carries a lot of responsibility (most do), work has to be the highest priority in your life. I knowingly and willingly sacrifice my health, relationships, and other opportunities for the benefit of the company. The company is becoming large and with that; communication becomes difficult, bureaucracy sneaks in here and there, and the environment loses it's scrappy, entrepreneurial feeling.