Pros
I really like the work atmosphere and people I work with at CGI. Although I cannot speak from personal experience, I get the impression that other similar consulting companies (Accenture, Booz Allen, ect.) are more demanding of their employees. At CGI, things seem a little more relaxed. I typically work 40 hours a week, and have all my weekends off (of course there have been a few exceptions to this rule). Also, the people that I work with are great. They are smart and work hard, but are also fun and easy to get along with. I also think the work we do is interesting. I think the benefits are really good overall - however, the 401k match could be improved. Finally, the company seems to be doing fairly well.
Cons
The pay might be a little less then some of the more demanding companies I mentioned above; however, I still feel I'm paid a good salary.