Pros
Cisco is a fantastic company in terms of benefits - I've never worked for a company that offered more. Salaries and bonuses are good, but there's much more - all kinds of insurance and health-related programs that help both the employee and the community. Always something interesting going on. Always a chance to get involved and do new things, both inside and outside of work.
Cons
It is painfully hard to get things done. Every department and every project and every process seems to be in flux all the time. Too many hands in every pot. Processes are too cumbersome. Too many meetings, too much confusion. It's a big, big company, with all the usual big-company problems. Note: this perspective is from a person who joined on as a result of her smaller, privately-held company getting acquired by Cisco.