Pros
As one of the country's largest employers, from a career development standpoint Lockheed Martin is a well established community that helps you define a path to progression within the organization. It comes with plenty of benefits and a 9/80 work schedule with provides a good work life balance. If you're someone who wants to get a job, isn't focused on an accelerated career path and is okay with riding it out. You can comfortably spend your whole career at Lockheed. Being a cost estimator follows that same story, you can have this job and coast for a while if that's what you want to do. The people for the most part are great.
Cons
Lockheed Martin, like many other big corporations, is NOT a meritocracy. Office politics, bs training sessions, a rigid management structure and a lot of people in bs positions. (Button pushers) Training is virtually non-existent. Unnecessarily long learning curve due to poor employee training practices. Don't expect much in terms of compensation, HR likes to lowball you and the organization likes to dangle a lot of carrots in front of you to get you to stay. Lots of office politics and poor foresight on the part of management to make the best decision for the organization at times. The job is relatively boring. Don't expect to be someone who's going to make a ton of money or even more than average in your area