Pros
You'll get exposure to many different jobs because they move people frequently. If you're in management working with clients you'll learn a great deal about negotiating deals although ethics are often questionable. Management salaries are reasonable.
Kontras
Shady ethics, little stability, no loyatly to US employees, if you're not part of the "brotherhood" it seems like you're really not part of the corporate family. A large majority of the staff are from abroad and the culture is influenced dramatically by that. As a result even when working at a US site it is easy to feel that you are working in a foreign company and that you have to break into that culture. It tends to be very closed and often you may enter a conference room to find everyone is speaking a foreign language.