Ventajas
Lockheed Martin had a very good program called ELDP which was great for obtaining breadth and learning a lot of new technologies and domains. Additionally, being in ELDP, Lockheed will pay for your full grad degree, up to a pretty high maximum. Lockheed has a lot of very engaging government contracting programs, it may take a few years of maneuvering, but you could find a very interesting and enjoyable job at Lockheed. Additionally, Lockheed takes care of a lot of there people. Especially if you have the right set of managers, you could easily stay at Lockheed your entire career.
Desventajas
The pay for performance structure seems to be slightly broken, and during uncertain times it is very difficult to get a promotion, even if you exceed all of the requirements. Additionally, a large portion of the developers in the company are being moved to a services pay ledger which will pretty much freeze any pay increases that you were expecting in the next 5 years. ELDP has been significantly modified, so it is not nearly as attractive as it was before. For example, when I started my master's degree Lockheed agreed that they would pay for the full degree as long as I worked for them at least a year after the degree. 1 year into my masters degree they changed this requirement to 2 years. Additionally, when I first started at Lockheed their health insurance was quite affordable, in my 5 years it has gone up over 400%. My yearly pay raises barely make up for these increases.