Pros
It is a highly professional organization that attracts professionals from all walks of life. If you do your work correctly, on-time and as planned then your relations with managers, supervisors and upper level employees goes very smoothly. They reward competence and that is what makes for a wonderful sense of team spirit that pervades the company.
Cons
It all depends on what division or department you are in as to the working environment and the level of job satisfaction. All divisions are not created equal and as such there is the chance that you will fall into a division that treats you less well. When overseas, for example, two different consultants working for COWI can have different supervisors and get a completely different opinion of who is doing what to whom. This lack of consistency could be considered a limitation.