Pros
I worked at SN for about 3 years, and was really able to grow my career. They did a good job figuring out what I was good at, and putting me in a position to succeed. Many people are given training on the job, which is invaluable in today's job climate. The dress is casual, the kitchen is stocked, and the technology (computers) could not be better. The managers and directors are very hands on, and do not shy away from communicating with you.
Cons
No major cons when I look back on my time at SN. Work hard if you want to see results. If you live in the city, this is a brutal commute, but you should know that if you accept a job in the suburbs. I am not sure if the policy has changed, but you are expected at work regardless of weather conditions.