Pros
There are some extremely talented and great people. There is a lot of variety in the work which keeps it interesting. The scale and scope of the projects are very large and the work is enjoyed by millions of people worldwide. From that aspect it can be rewarding.
Cons
Everyone is expected to work a lot of hours. For several weeks when I started I was working around 80 hours a week. Eventually I worked it down to 50-60 hours a week. Some upper management were egotistical and seemed a bit unappreciative of all the hours being put in. It was just expected of you. It is a very fast paced environment making it difficult to put a lot of thought into your work. Upper management would literally walk up and down the aisle saying "work faster". It was very stressful. The company as a whole was hard to adapt new methods and technology. At the time we were probably 15-20 years behind other design offices in terms of technology. Much of the senior staff was a bit closed minded and not open to newer software or equipment that would benefit the company.