Pros
The other collegues I work with are great to work with for the most part. I feel that my career has progressed at CGI in terms of more responsiblity and more technical challenges. The work environment is also pretty good.
Cons
Your work is subject to the client's demands. That is the frustrating part about consulting in general. A lot of your experience at CGI depends on the Business Unit you are working in and the client you are working with. You can get locked in to working with a certain client and it can be difficult to move especially if you become a key resource with your client. I was unhappy with my compensation for a while but I recently got a decent raise so it did help. But I feel that some of the increase in compensation was due to the fact that many good people were leaving.