Pros
Work/life balance is typically very good. Lots of upward mobility opportunities for software developers. Great opportunities to learn a lot very quickly from incredibly talented and intelligent colleagues. Excellent overall attitude of employees. Free lunch and low-cost medical/dental/vision plans (for US-based employees). 401k match is on par or better than nationwide average.
Cons
Infrastructure is aging badly and directors are not willing to spend any kind of money engineering time on improving corporate workflows. FactSet from 5+ years ago used to be known for implementing new technologies and always being on the cutting edge, but now this is only true for the favored few. Base salary is below average, especially when compared to other technology companies. Year-over-year compensation increases are often laughable, and internal promotions lead to insulting bumps in pay. Well-qualified and Senior engineers who do not come directly from college or from an external company are paid FAR below company averages. Bonuses are no longer given for specific teams and departments. Career growth for anything that handles infrastructure is non-existent. Too little direction from certain managers with a lot of unclear objectives and weekly reordering of priorities.