Ventajas
If you like working for a company with long term job security with mediocre performance and wage increases this company is for you. If you're ambitious and driven.....its a death trap. Lockheed has AMAZING benefits in terms of 401k, paid time off, and overall work/life balance. If you have a family....this is the company to work for. Expect little to no overtime (unless you want it) and the availability to take vacation whenever you want (regardless of any work obligations)
Desventajas
In terms of performance and promotions.....you're locked into a nightmare. My initial offer from the company when I hired on after college was comparable to all the other offers I received, but you'll find that once you're on the inside Lockheed does not try to keep up in terms of what the going market rate is for your years of service. If i look on glassdoor and other websites the average salary in my area code is generally in the range of low 80's to high 90's. Where as i would have to work at the company for on average another 10 years to make that kind of salary.