Pros
Generally speaking the work environment is very flexible, as long as you're producing quality work. The compensation was reasonable, but it varies widely based on what group you're in and what projects you're working on. The newer projects obviously get priority when it comes to budget, as well as the workload.
Cons
As said in another review of Cisco that I read, it is very easy to slowly get sucked-in and end up working 14 hour days. Generally speaking, you will be rewarded based on what you put into it. So if you choose to put up boundaries and stick to a 40-hour week, you'll be comfy and cozy. If you choose to put in 60-80 hour weeks, you're likely to be elevated in the long term (provided you're not in a group that's approaching "sustaining-mode" where there is very little new development). If you're lucky enough to get into the "in-crowd" and you're a hard worker that puts out quality product, you're set for life. Cisco has a very elite group of people that jump ship every few years, create a new start-up (i.e. ensime, nuovo, andiamo), work their tails' off, get purchased by Cisco making tons of money, and repeat. But getting into that group is extremely difficult even if you're good at what you do. There's a bit of class-ism in the Cisco HW department.