Pros
The pay is okay. There really aren't many other pros that I can think of. They're a large company, and some people might like that.
Cons
There is zero opportunity for growth. The company is in decline and the senior management either don't care, or just want to squeeze every ounce of blood out of it before it dies. It won't go any time soon, mind you, but it will go. The amount of process that one has to go through to get ANYTHING done is nothing short of staggering. Process, schedule and cost come before anything else. While Lockheed hasn't been caught up in any recent ethics scandals, they apply very little ethics in how they treat their employees. They are not reinvesting any money in the company. At all. You can't even get them to buy a paperclip, never mind the proper equipment for the engineers to do their jobs. To sum it up: Poor management, no reinvestment, treating the employees like crap, no vision and management by process have brought a once great company to its knees.