Pros
Lockheed is an excellent employer for entry-level engineers. Their overall compensation and benefits package is fair, but where they really excel is in providing training opportunities for those who are interested. If you take advantage of them, Lockheed's leadership development programs, technical training classes, and tuition reimbursement benefit can be invaluable for professional growth. Obviously, they have a vast amount of geographically and functionally diverse job assignments if you are seeking variety. In general, Lockheed has a very flexible work environment and will try to promote a positive work-life balance.
Cons
As with most large corporations, salary bands and job levels are strictly managed by HR. For those who came in at a low salary, or who gained significant experience during employment, this process effectively keeps you at a below market salary. Exceptions can be made for certain employees; whether they are rewarded for being the the most outstanding or most well connected is debatable. As an entry level employee, if you've outgrown your salary, your best bet for getting a raise is to speak up. If that doesn't work, leave (for a much higher salary) and come back.