Pros
Being a young company, its a unique environment to be in. Everything is always changing and developing and it's really cool to watch employee ideas grow into company wide products and procedures. There is a lot of opportunity for growth that wouldn't be as widely available in an older company. The customers are wonderful, the established products are really cool and the upcoming stuff is exciting. Benefits are great (90% coverage for you and all dependents) so although the starting pay may not be as high as other places that helps to average everything out in the end. There are fully stocked kitchens and drink areas, a wellness program, and an incredible group of coworkers. Everyone spends a lot of time together in and outside of work and overall everyone gets along very well.
Cons
The fact that it's young and everything is changing all of the time. Procedures and processes will switch on a weekly basis and not everyone will be on the same page. Programs and systems can get frustrating because they have not been updated as quickly as the growth and product changes would need to be smooth. You will work a lot of hours during some months. Long days (12+ hours) and long weeks (mandatory extra days). Certain departments have a lot of stability and others not so much which can be frustrating at times and make promotion/changing departments a scary venture.