Pros
All the individuals who I worked with at FactSet were fantastic. They're all motivated, skilled, and eager to help out coworkers. In ten years at FactSet, I never worked with anyone I wouldn't happily recommend.
Cons
In the ten years I worked at FactSet, communication between teams, individuals, and management progressively deteriorated. The problem accelerated when many experienced engineers started leaving, and left their systems unowned, because nobody else had the knowledge necessary to maintain them. Management seems to think that when someone leaves, they can just assign a new person the job of being the expert on their product. But there's rarely any decent documentation, and no clear plan for transferring knowledge to the new "expert", so they're often left scratching their heads. The use of "microservices" has exacerbated this problem: Now it's often difficult to find where the relevant code base lives. It's often split among dozens of interdependent projects that are hosted on multiple different cloud hosting services - and very little of this architecture is documented. In general, all the individuals who work at FactSet are great, but they're constantly held back by a lack of basic information about the company's systems and products. By the time I left (2021), my job felt more like archaeology than engineering, because I spent nearly all my time trying to figure out how our existing systems were designed and what they were meant to do.