Pros
Industry leader in many ways with one of the best brand-names in the business. Fidelity at the top of your resume or anywhere on your resume gets you noticed in the marketplace. It's a private company instead of public company so it's not pressured by the Wall Street quarterly earmings mentality, and that's a HUGE difference-maker in a great way. It's a well-capitalized company and they spend a lot on technology; I've honestly never seen anything like it. Some very smart people there, too, and some of them were even nice. Fidelity has a variety of businesses within the organization and people do move around.
Cons
A lot of uncertainty from the top down, and most rank-and-file employees feel very out of the loop and not very empowered. Restructurings and management changes seem to be arbitrary and tend not to improve things; it almost feels like someone's tinkering with things because they believe they need to do something but they're not sure what. The people at the top are absurdly over-compensated and they don't spread it out as much as they could and should -- more employee ownership would be a great step. The people on the "inside" of the fund management shop, the core business, seem insulated and out of touch, kind of like a bunch of Roman senators.