Pros
Awesome co-workers! Everyone is very friendly and cares about you. Free lunch (when you're in the office).
Cons
Management (all levels) does not value strong leadership skills for becoming a manager. Their promotion process is more of a popularity process, so there are a LOT of managers who should NOT be managing people. They may be wonderful at managing projects, but that's a completely different skillset than managing people and FactSet dismissing those people skills (while you're reviewed on them as a manager, they barely factor into the conversation, nor do they impact your salary). I was there for many years, and was consistently disappointed with the poor leadership. Moving up in the organization is never a clear path (again...popularity rules here), so it's very easy to get stuck in a role.