Success and happiness vary considerably depending on department, overall good company.
Pros
I just passed my 10 year anniversary and am still proud to work at Cisco. The benefits are varied and quite good, lots of vacation earned (6.16 hrs / pay period) and caps at 280 hours. Lots of non-monetary rewards like gymnasium, child care, dry cleaning, car wash, new medical facility, free soda and water (although not for long), and telecommuting options (although this varies greatly by group and manager), the pay for my monthly home broadband too ($62/month). Lots of on-line education and the tuition reimbursement is great ($7500/year). Fortunately I work in a fairly decent group (marketing) with minimal politics except for a few highly volitle people. I have an engineering background so like the mix of business and technical. If you're a technical person, it's a pretty good gig.
Cons
I don't know where the many people who wrote reviews here work who said there is good work/life balance because I've never seen it. I have never worked less than 55 hrs/week and often 80+ hrs. There absolutely are duds here who are great at talking non-stop and so get recognized but they don't do anything. I get frustrated working at a high tech company and constantly get asked stupid questions about how to use Excel or PowerPoint or things they can easily look up themselves. How can someone get a job here and not know computer basics is beyond me. Just because they're busy doesn't mean they're productive (basic computer skills would be a great improvement). I also don't like the performance review system which many others mentioned. It's an absolute joke (and not a good one). Your score has little to do with the quality of your work, but how much your manager likes you, how much work s/he is willing to do to help you get ahead, and how lazy they are. I've had managers tell me they never give an X (the highest score) no matter what you do and everyone gets the same rating because it's easier for the manager. I was fortunate to finally get a promotion last year (and two raises) but it was a horrific, butt-kissing process. I've had over 15 CAP awards over the years but none of that seems to matter. You can do the exact same work for manager A and get a E score but then move to manager B and get an X, it makes no sense and there is no oversight or standards.