Red Hat is a great place to work at a great time in it's life, but not without putting in much hard work.
Pros
A great business model, many talented people, much opportunity, interesting technology, exposure to high-level leadership both internally and with your customers, opportunities to work within high-impact projects at Fortune 500 companies. There are almost too many good things to tackle at once at Red Hat and it can result in growing pains at times, but the culture is generally one that succeeds when it is all said and done.
Cons
There are many times where you find yourself lacking resources, dealing with immature or disorganized processes, and often just plain tired from sinking much time and energy. But there is nobody standing in your way preventing you from coming up with a solution to the problem and making your mark in this relatively small company with a big brand.