Pros
The concept(s) for what their web site is supposed to be, along with the creativity of the design team, and the talent among several of their developers I worked with are one of the most talented groups I've worked with as a whole. Their business model, if executed properly could really take off. The nature of the business model means you will be always working with all of the newest technologies and will always be on top of all of the latest trends.
Cons
The core problem with this company stems from completely unrealistic expectations from the top down. There is a large disconnect between the artistic and technical sides of the business and very difficult to create a consensus between the two. You will be expected to work an obscene, ungodly number of hours... I am talking in the range of 80-120hrs per week. You can expect phone calls at 3am on your weekends (in which you will be working anyway). In the highly unlikely event you ever reach a milestone on time, it won't matter because the bar will just get raised higher and you will still be held accountable. They even fired one guy the day after he had a baby if that says anything! There is a very high turnover rate as they "churn and burn" through the talent they hire.