Pros
FDS has a very nurturing atmosphere that allows software engineers, especially those coming out of school, to grow their skills and learn from the software industry. They are very happy to have their engineers go to conferences, read books, and learn from each other, and ease you into the professional software process with tutorials and lessons. They also prepare you for management after you've shown the ability to take on the responsibilities, and are supportive if you want to stay a pure software development role as well. The people there are a ton of fun to work with, and are hired from the best schools in the country.
Cons
The biggest problem about working for FDS is that they're a financial company masquerading as a software company. Things move very slowly, even in the heart of silicon valley, and FDS's big banking clients are not receptive to any huge changes, which makes for slow, even outdated technological development. Beyond that, the company seems to value its salespeople more than its engineers, which makes for some frustrating experiences as an engineer when dealing with upper management on even trivial issues. This issue is made worse by the San Mateo office location, which is a remote office and has to go back to headquarters for any significant decisions as well as higher promotional opportunities.