Pros
Competitive benefits (dental, vision, medical, gym, subway) computer & cell phone, beautiful office space, coworkers will likely be your friends. Generally, everyone there is good at what they do. You don't feel like you're dealing with idiots. Very lateral structure - there is limited bureaucracy and things move fast. Few, if any, people you have to go through to get an answer. You will get a lot of experience and you have a lot of responsibility.
Cons
They will burn you out; Don't expect to stay longer than a year. There is no work life balance and you are nothing but a battery to be exhausted. You will have a managers, but not a leaders. Laughable pay, especially considering how much they ask of you. Things to keep in mind: If you don't work in NYC, don't expect do move up much, especially in a newer office. Typically people quit after 1-2 years in exasperation and lack of vertical growth opportunity. If you see it as a stepping stone, you'll be fine. The hiring process takes months. Don't be surprised to go in for 4 or 5 interviews over this time and then be approached you with a different position. Hard work is irrelevant - either you produce results or you're out. Don't expect a bonus, even if they tell you you're getting one. The excuses are as wide as they are diverse, especially if your salary raises were in the form of a bonus. Inappropriate sexual misconduct is common and so too is inaction or mismanagement of these cases.