Pros
For the most part, you'll work with smart, passionate people at Leidos. The projects are interesting, challenging, and diverse. There's general trust in the employees to balance work/life (depending on the manager). There are global opportunities to work on cutting edge technologies and solutions.
Cons
Like any large corporation, it all depends on where you work, who you're teamed with, and who your customer is, so it's hard to give generally applicable feedback, but one area is communication. There's a lack of meaningful communication from all levels of management. Both new and long-term employees have ridden many waves of change over the past several months and years. This leads to change fatigue which is only alleviated by clear communication on why the changes are occurring and what the future plan is for both the overall company and the individual employee. When employees are uneasy, and many opportunities can be found outside of Leidos, the company should adjust its approach in order to retain great talent.