Pros
NASA Ames provides employees with the opportunity to work on small spacecraft missions early and often. This provides valuable hands-on experience as you navigate the full life cycle of a project (phases A through E) in 2-3 years, as opposed to once or twice in your career on larger projects at other NASA Centers or large aerospace companies. The work/life balance is unprecedented (especially compared to other employers in Silicon Valley). The salary is lower than other nearby companies, but the true value of a job needs to take into account many other factors, such as schedule flexibility (start/end times are flexible to avoid traffic and working from home is an option 1-2 days per week for many), rewarding and challenging work with a purpose, stability, and time expected at work (40 hours per week is the rule, not the exception).
Cons
Traffic is a killer (but most have flexible schedules and/or work from home on occasion to avoid the bulk of it), the salary is not as competitive (no stock options or huge annual bonuses, but value is found when looking at the whole package), and the smaller missions don't get as much press as some of NASA's larger missions (but the shorter life cycle and increased responsibility and hands-on work comes with the smaller missions). The weather is sunny and temperatures modest most of the time (for those that like seasons).