Pros
Excellent atmosphere. Red Hat is a large company but still seems to retain some of the smaller start-up culture it started out with. If you come to RHT don't expect handouts or to be led along, it's a company for driven individuals where great communication skills and resourcefulness are rewarded.
Cons
As the company grows it's attracting individuals who aren't exactly the right-fit. As a result the culture is being negatively affected. There's also some pay issues. The market rate for roles is completely out of alignment with some of the people who've been around at RHT for a number of years and have ascended within the company. This results in the attrition of people who are offered a significant increase in their current salary to move elsewhere. These are key people at RHT and losing them costs the company more than the difference in their current salary to the market rate.