Pros
There is a lot to learn, many projects/programs are CMMI Level 5 so you will have great support in producing reliable, high-quality software. In St Louis, there is also an internal rotation program for software engineers so that they can move between projects in the St Louis site by doing a simple, informal interview. Work-life balance is supported, software engineers are paid overtime, and in general flex time is allowed. Work at home is also allowed for some projects.
Kontras
The software engineering population in St Louis is aging. The staffing profile is top-heavy, and for this reason they have announced a freeze in promotions for most software engineers this year. Some of the software is older, so if you're looking for cutting-edge software technology you may or may not find it depending on what program you're working on.