Pros
Red Hat has some great people particularly on the technical side. They have develop some great solutions and technologies that have change the market place certainly with Linux Red Hat and Jboss. Great place to be if you are developer. Lots of good interesting projects to get involved with. New ways of thinking and a real chance to develop your skill set to your own benefit.
Cons
Red Hat are making that transition from startup to enterprise, certain people cannot make that change and are holding the company back. Expect to be micro managed, expect a culture of blame down from some managers to their team and individual contributors. The company wastes a lot of time on reporting who is doing what, so much so that they are wasting huge amount of resources doing so. There is a strong sense of dis-jointment between the sales and the rest of the organisation. As a smaller enterprise there is a lot of favouritism that goes within the organisation. If you are not one of the favourites do not expect much chance of career progression and be prepare used to further the career of others.