Pros
Great reputation of the Forrester name will help your resume. Good benefits. Flexibility to work from home, even though presence in the Cambridge political scene is key for getting promoted.
Cons
People are horrible, non-collegial, and often non professional. Analysts have huge egos and they often lash out at colleagues, and especially at more junior people. There is lots of criticism, most of it petty and un-constructive, and no praise. There is no collaboration; in fact, teams are set up in such a way that they compete for the same revenue from their clients. Client needs and quality of research are not a priority, and the client experience is poor as a result. Groups are too siloed for such a small company. Management is poor and and demotivating. Morale among employees is low. There are no clear growth paths, even though there is a complicated process that supposedly lays out career paths. Noone follows that process though. Salaries are low compared to the market place. Stress level is high and you are expected to work evenings and weekends. Management is random.