Pros
The best reasons to work at FactSet are: 1. work/life balance - engineers here are not overworked, and I think they are more productive because of this 2. hands-off management - you get a lot of freedom when developing your projects, and there is little micromanagement 3. atmosphere - it is a very collegial environment, with people doing serious work but able to have fun at the same time
Cons
The worst part of the job is knowing that you are in service to the evils of Wall Street. It is easy to look past this for the sake of quality, enjoyable engineering. FactSet also has to compensate engineers more generously in order to stay competitive with hiring/retaining quality engineers. There is stiff competition in this regard from Google, Apple, Microsoft, Amazon, etc.