Pros
The company works on really interesting cutting edge technologies. Also, the benefits are great. There is a lot of opportunity to move around the US and the world in different jobs. Also, there is a lot of growth opportunities considering how hard Lockheed Martin will be hit by all of the retiring baby boomers.
Cons
At Lockheed Martin, it is expected that you do a good job, most everyone does. Because of this they have a some what backwards methodology for promotions and advancement. If you do a great job, and focus solely on it, then you will be a good employee and will be able to retire happy...at your current position, and with minute salary increases year over year. To really get ahead with this company you need to take stretch assignments and put yourself out there in ways that are outside of your day to day job. This way you can get noticed by the corporate level management and really move up the ladder....and make some real money. Otherwise, your friends working for companies that make consumer products will always be making more money than you. Also you can kiss Christmas bonuses goodbye with the economy the way it is...especially if you work on a government funded program.