Pros
The greatest asset Millward Brown has is the strong base of smart people to learn from. Experts are very accessible and are willing to jump in and help. Great people around to mentor career development. Big company with a long history means there is a ton of knowledge and resource at your fingertips, but also can have the benefit of a "small office" environment if you work in one of the satellite locations. Very good portfolio of different client industries to work with. Great place for people who enjoy both Analytics and Creativity; more "fun" than the standard research job. Great benefits, including flexible work hours, good work-life balance, and ability to transfer to offices across the globe.
Cons
Training program could be improved