Pros
Opportunity to meet and work with people in different nationalities and culture. People are given freedom to express their creative ideas... but the approval and/or granting of the required investment to completely realize it is entirely a different matter --- usually, you have to invest your personal resources to make it happen.
Cons
A flat organization and close to having no structure is prone to chaos. Without a professional HR personnel, determining the growth of employees (and their department) is very unbalanced, biased, and rely heavily on public relation skills more than technical prowess. Insistence of very traditional behavior especially from most of the higher-ups tend to slow down and restrict progress. There is minimal support given to technology-based approaches and projects. Even though there is a small budget allotted for training technical personnel, there will always be no time to dedicate for it because there is just not enough manpower to provide services to everyone.