Pros
Learning curve: Here you will have the opportunity to learn from different business models and have a lot of ownership over your projects which means the experience can be brutal and isolating (not a lot of training or mentorship going on) but you will take a LOT from it. You'll learn what others do in a year in a just few months... or you'll get burned and leave. Colleagues: Kind and bright people, even if the culture of the company is not 'friendly', employees try to create a warm culture by themselves within their teams. Very multicultural. Career advancement: If you want to go up the ladder quickly this is an electric escalator. If what you want is a fancy title for your CV or LinkedIn profile with "Head of something", "Managing Director" or "Global Senior Manager of whatever" this is the place, but you'll pay the price of crazy (fantasy) targets, long working hours and uncertainty.
Cons
If you come from any a big tech company or an employee centric startup, forget about your perks. The culture here is not thought as a mechanism to make employees happy. Huge turnover. You'll work with co-founders, CMOs, "Heads of something" from different ventures. Some are cool, but most are entitled, arrogant kids (90% male), almost fresh out of their master studies, Morgan-Goldman/Boston-Bain ex-interns.