Pros
High emphasis on a fun work culture and team building. Innovation and new ideas to get things done are welcome and valued usually. There is a strong belief that talent trumps skills (ie that successful and driven individuals can take on new tasks and job roles) and the upside is that most roles will allow you learn widely what might take you years to gain experience in at other companies.
Cons
Overly competitive, numbers based work culture that often led to shortcuts and passing problems down stream in the work flow. The fun work culture sometimes made it difficult when you're one of the few team members that have a family. Certainly there's a feeling that certain individuals are "in" and rising stars and others ignored or frozen in their career path, leading to a very fierce competition to be on the inside. When I left the company I found out that I was able to make 40% more in a less demanding position at another company and others even more.