Pros
Cisco is one of the best places that I've ever worked. Even among other IT companies such as SAS and Google, I think Cisco stands out as one of the best. (Okay, Google was really good too, and possibly cooler, but I still say Cisco is better.) Why? I can sum it up in one word: culture. The people here are amazing, and always willing to help you out and help you grow in your career. I've never loved the place and people I work with more. It's also a very good place to build a career, with a lot of lateral movement within the company. And if you're willing to work at it there is a lot of opportunity for advancement as well. Just be prepared to work harder than anyone else if you want it.
Kontras
The work/life balance is a little skewed towards the work side. But they have seminars on just this topic. It's not as crazy as Google, but I do spend more than 40 hours a week at work fairly often. Luckily Cisco allows you to work from home, so you're not stuck in the office the entire time.