Pros
Salary numbers are generally pretty strong. Very diverse array of projects to work on.
Cons
Once a stable career path for many engineers, Lockheed MST has done pretty much everything they can to turn it into a short-term destination for job-hoppers (the Obama vs. Tea Party battles that began in 2010 haven't helped, either). In the eyes of the company, the systems engineers are the people that do the real work that keeps the lights on; the software, electrical, computer, mechanical, etc. engineers are "The Help". If you fall in this category, you have absolutely nothing to look forward to in your career but being bossed around by a gaggle of the same interchangeable "smartest guy in the room" types that seem to exist at all East Coast defense contractors before your eventual layoff. Company doesn't believe in training engineers in practical skills to improve retention. In software, acquiring new tools, even under LGPL, is an unbelievably arduous and lengthy process.