Pros
LM generally has excellent job security, except in times of constrained gov't budgets (such as today). Even then, one's position is not in jeopardy provided they seek out active projects or perform well enough that active projects seek out them. Benefits are strong, although LM has been retooling them lately due to cost issues. The newer options are universally regarded as being of poorer quality than the previous system. Business practices and processes are well-documented, and usually well-followed. LM does a good job at designing job roles to be trainable and then training employees to perform them.
Cons
LM has lost a good deal of its strategic vision, especially when it comes to innovation. It seems a growing percentage of contracts are operations and maintenance as opposed to development. These have the same people doing the same tasks for years, if not decades. Technical stagnation often ensues. LM also strives to make jobs performable by ANY employee of the appropriate title, rather than those that are exceptional in some way. This generalization of roles means that LM often can get away with using employees of substandard abilities, which allows them to pay lower salaries overall.