Pros
The team is amazing. The owners/executive team really focus on hiring motivated people with shared values, instead of just hiring a skill-set. Skills can be learned, but values, motivation, determination, and teamwork is either there or it isn't. There are near infinite advancement opportunities if you are driven enough, which is great too.
Cons
The "start-up" mentality can be challenging for some people if you're used to having very clear tasks and don't perform well if your job description isn't evident at all times. However, this lack of rigidity is very motivating and fun for other people, so it's really just a matter of what type of person you are.