Pros
Arup does have some incredible people in its ranks. Strong leaders, diverse in places and leading the way in certain industries. A good internship program (in some areas, dire in others). A broad range of work, when it's there. Opportunities to grow, if they like you and you fit that one sort-of-yes-man-shaped mold that they're looking for. Nice locations, rooms with views, but there is so much more to life, right?
Cons
The grading system is a farce, you'll get nowhere without moving about or leaving, and returning. You'll be promised the land, the oceans and the kingdoms, you'll get the minimum, but they're very good at keeping you on the hook. As one of the reviewers above put it, it's a boys club, you'll go far, if they want you to go far. Work life balance is a myth. The profit share is just a way of making it sound like some organic, we're-all-in-this-together environment, but it suits the top echelons, and if you're anywhere below a 6, you'll be lucky to get a few pints down the local.. The culture of Arup, which was at one time the glue that kept everything else in place, is just a pretty little view in the rearview.