Pros
One of the best reasons to work for Lockheed is the ability to take advantage of the numerous oppertunities. You have the option of moving horizontally accross different job functions, moving to different projects, or moving to a different location altogether. Lockheed is located all over the country and even overseas. The type of work Lockheed is involved in is diverse. The Owego facility alone specializes in project from many different industries. For those college hires there are great programs that can be taken advantage of, such as LDP, where Lockheed will help you get your masters while giving you the oppertunity to move around the company to find what you like.
Cons
Lockheed is a large company that can seem overwhelming at times. It is easy to feel lost at the company unless you put forth extra effort to stand out. It's also an older traditional type company where managers believe that people need to put time in before they are rewarded. One major downside is the overall "slowness" of the company. When I started, it took management several moneth before I had enough work to occupy 40 hours a week. However, once you start getting work, overtime is common. Work on projects also tends to be slow moving because of all the government involvement. The US government isn't always the most cooperative of customers.