Pros
Overall, I really enjoyed my time with ManTech. Salary and benefits were fantastic. Managers had a "hands off" approach, giving you the autonomy to do your job without micromanagement. They were always supportive of any employee needs, which is relatively rare in this industry.
Cons
Just like any other contracting position, job security can be a concern. The company touts its "Career Mobility" program as a way to transition "at risk" employees (those who's contracts are ending) into new roles within the company. When my contract was set to end early, I promptly applied for a similar position that my resume fit perfectly with. As an "at risk" employee, I hypothetically had priority consideration for the position; however, I never even received the opportunity to interview and they extended an offer to a candidate outside of ManTech. The customer won performance awards for my work, and kept ManTech in their good graces, thus this was a hard pill to swallow. So yeah, take that "Career Mobility" program with a grain of salt...