Pros
Never boring, always improving. You will meet some of the best mentors in your life, they will help you grow and develop a successful career. Start up environment will ensure a constantly changing company structure, lot's of room for career development and mobility. Good bonus pay out, especially if you hit KPI and goals. Lively environment. People are energetic and fun. Your peers will have tons of good ideas and you will make many friends. Management really care about their team members. CEO is a funny dude, if you get to know him you'll really like him. He comes up with a lot of different ideas, and that may overwhelm some people, but if you talk to him 9/10 times he'll listen to you, even if at first he says "no". He will think about what you said.
Cons
Average age in this company is very young, you will meet some immature people who can't differentiate between work and life. A bit understaffed, some positions are overworked.