Pros
Great colleagues. Forrester is a great place if you're interested in surrounding yourself by intelligent people. There is a great buzz of information around the office, you can really engage with people around you on some interesting topics that range from research on marketing, financial services, etc.
Cons
The pay is pretty poor, especially for New York standards. At the end of the day the impact of the company feels rather shallow. The whole business model is rooted around trying to be a "thought leader" in the MANY verticals the company focuses on. The quality of research used to support this model is rather poor in my opinion. A research engagement basically consists of aggregating qualitative interviews from executives at different business. The only data used is survey data that in many cases is hard to access due to cumbersome internal processes. If you look at the way companies are operating now, what's the appeal of going to this outside entity when all the data relevant to optimizing business performance can be aggregated and actioned upon internally? Forrester feels like a dinosaur company flailing for relevance in the modern era of advanced analytics and data science.