Pros
The company truly values employees and customers. The commitment to work/life balance comes from the top down and they believe in it. As a result, employees treat each other fairly and well. There is a tremendous sense of camaraderie. And the benefits really are top notch.
Cons
Nobody ever leaves, so it can be hard to move up. There are a lot of smart people there, and a lot of hard working people, but also a lot of people who don't seem to accomplish or contribute much other than add to the process. The "no layoffs" mentality, for good or ill, means that SAS never undergoes the clean up of the dead wood that routinely happens at other companies. The culture of consensus means that nearly anyone can derail a project, even if it has little or nothing to do with their area of responsibility.