Pros
I've been working as a full-time employee at Edelman Berland for over 3 years and have had an incredible experience. It's a start-up within the establishment that is Edelman with its own identity and culture. While Edelman can have up to 800 people in an office, Berland teams remain boutique with only 12 - 20 in each office supported by the company's headquarters in Rochester (which has 55+). It values talent as much as experience and there is always room for advancement at all levels. The people you will be working with within the Berland network are the smartest research professionals recruited from top schools and top firms. Working at Edelman also has the added bonus of working with amazing clients, and on any given day a dream assignment could land on your desk. It is a work hard culture, but the hours are manageable (the office is basically shut down by 7 PM). There is a lot going on within the network as the company moves to support Edelman's vision of Communications Marketing and Edelman Berland is pushing the envelope to stay ahead and continuously innovate itself.
Cons
This is not a 1990's research shop. It is a company that is constantly evolving to integrate tools that encompass primary, secondary, and analytics research. So, there is some change as you go though I have never found it disruptive.