Ventajas
Lockheed Martin is an easy company to work for. Not much is expected of you, even if you're part of a "high-potential" group, and you can skate by with minimal work. The salary is decent. A lot of the products that Lockheed Martin makes are incredible and it's cool to get to know how the work is done.
Desventajas
Lockheed Martin is not challenging and most of the work is not interesting. Lockheed is a 100 year old company and they have been doing things the same for many, many years. Being in Silicon Valley, it's extremely hard to know people at companies like Facebook, Twitter, etc, who absolutely love their jobs and have fun when they go to work every day. Lockheed's compensation is also a disappointment. The salary is fine, but there are no bonuses or incentives of any kind unless you get lucky and get some sort of stock award. It's also frustrating as a young, ambitious person to see Senior Manager and above management be completely incompetent. They made it into their positions because they've been around for 30 or 40 years and that's really not a good enough reason for them to be in a leadership role.