Pros
Having worked at a few research firms in the industry, I found Pollara to be the place that had the smartest people, did the smartest work, and most of their clients and projects were the kind of stimulating challenges (that we would apply really innovative approaches to) that researchers dream of working on. Also, the senior management is very compassionate and understanding with the team and also committed to mentoring as well as recognizing talent and hard work.
Cons
They are boutique size, although always growing. Still, not a behemoth like some of their competitors. Some people prefer the big multinational sized firms. I thought I did, and went to one - but didn't like it. Now, I'm working on my own, which I like and makes sense for my personal situation.