Pros
The money, especially bonuses in my experience exceed the market. The base salaries are about on par. There are a lot of good benefits beyond 401k and health care. There is supposed to be a work / life balance at Fidelity, but like so many other things, it is very inconsistent from manager to manager and business unit to business unit.
Cons
The company has institutionalized the acceptance of failure at worst and mediocrity at best when it comes to IT Projects. As a software professional, it becomes frustrating to work furiously at solving every type of issue besides the technical. Front line managers are ill equipped to manager software professionals, they are either bad developers promoted to the point of incompetence, or just do nothing know nothing MS Project jockeys.