Pros
If you believe in Open Source, Red Hat is a great place for you. Most of the engineers are hard core open source idealists and they will argue with you all day long for it. Open source is a religion and a movement that many Red Hat employees hold true to their hearts and if you believe in open source, you will feel like you are fighting for a cause. In addition, Raleigh, NC is a great place to raise a family, with great infrastructure, good school, universities, hospitals and most southerners are friendly. You also have some other good employers in the area, such as IBM, Lenovo, Netsuite, SAS etc.
Cons
A lot of internal politics and Open Source is seens as a religion within the organization that sometimes people lose sight of the business. For example, many insist on using Open Source technologies internally without actually thinking about the business requirements and how mature some of these open source technologies are at the expense of employee productivity. In addition, internal politics abound in this place. You see managers fighting all the time and silos within this relatively young company. Many of the managers make decisions based on what is best of themselves personally, rather than what is best for the company.