Pros
Dependable salary, relatively straight-forward requirements, nice folks, pretty good work life balance (almost never stayed past 6pm)
Cons
As many as 11 layers of management will separate you from the CEO. This translates to a mountain of bureaucracy, with hundreds of internal groups, some deeply removed from customers. The group I worked for went by an acronym, and no one, not even my manager who had been there for 20 years, could recount what the acronym meant or how they came to get it exactly. Cisco seems to have an existing informal agreement with employees: we will hire you as a contractor, and one day, many years from now, you will become permanent. May be 2 years, may be 5. That's a long time for commitment in the tech sector, so it attracts folks who are willing to slog it out and are looking for long-term, safe employment. A newer model was developing as I was leaving, which is diametrically opposed to this, was outsourcing. So after toughing it out for years and doubling-down on Cisco, you might discover that one day a foreign employee on a visa, or many, many foreign employees with visas suddenly appear. It's your job to train them in how to do your job. Sound scary? It sure was to the 55 year olds I worked with.