I have been working at Cisco Systems full-time for less than a year
1. It has wonderful work culture. 2. It encourages it's employees to be "YOU", you have full freedom to be yourself and this is when they believe the maximum potential can be unleashed. 3. The... leadership is top-notch right from bottom to the top. 4. Cisco respects each of its engineers, and it gives you full freedom to explore your talent, and unleash the potential within you. 5. It produces ground breaking products that are worth the experience to be a part of and contribute towards the same.
Really? If you have many Pro's i don't even think even the marginal con s are not really a con. However, I don't have anything to share which would be a con.