Pros
It is a creative place that works with large companies. People are exposed to working with companies like P&G. It's is a young atmosphere where young and enthusiast people can learn a lot ( but not get much recognition for your work). There is a lot of excitement around projects and it can be very rewarding. High pace, with fun travel and you get to attend some fun events. Like most companies, there are some great people and some not great people.
Cons
GGI does not promote work life balance. Most people there are underpaid, however they can do this because they are a sexy company. Morale was low and trust did not existed. Much time is spent on writing CYA emails. People will point figures in meetings every chance they get. Limited recognition is given. Fear is used as the major management tactics. They demand you put the company first all the time. And management makes fires which everyone needs to jump to put out (of course at 5:30 on a Friday).