Pros
This is a fast paced, growing company that is going places. Opportunities abound for people who are willing to grab the bull by the horns and make a mark for themselves. It is a young company and so the individual still has the opportunity to make a mark and determine the direction and culture of the company. The size of the company allows individuals to have an impact on the company's success. I detect more than a hint of sour grapes from the negative reviewers. Every job has its flaws and shortcomings. However, the flaws for one person could be a strength for others. I sense a lack of fit in these reviews.
Cons
Given the pace, the intensity of the work, and the need to bring your "A" game, it is not for everyone. Moreover, the company operates in a dynamic area and thus it is always changing. If you are interested in working in a dynamic area that requires a certain nimbleness and a comfort with change, then this is your place. If you are not, well, there are other jobs and opportunities out there for you.