Vantaggi
If you get in the right cliques, you can transfer departments and offices readily. They have a history of winning work on big projects that will impress your friends and colleagues.
Svantaggi
My branch of AECOM had a toxic culture that nearly ruined my career when I just started out. The toxicity went from the senior management, who go on tours around the region quite literally asking us to think of the shareholders when we worked, to EITs forming cliques, keeping secrets, and hoarding work and advancement opportunities because there's not enough to go around. Even the office itself was depressing, with all gray walls and cubes, with a coffee and refrigerator closet that they called a breakroom. AECOM was constantly falling behind goals, reorganizing the company from the top down every couple of months, introducing disorganized intranet tools that take essays to explain, and taking days to fix their own computer equipment. It was very hard to be productive, especially with management never being around to advise and with unhelpful, cliquey coworkers. I heard from colleagues at other civil engineering companies that the joke goes around that AECOM is trying to be the "Wal-mart of Engineering", which sums up a lot of what I was talking about.