Pluspunten
Great place to start working in if you plan to work for a consulting company. The company is one of the biggest in north america so you'll get all the advantages of a company of this size like health plans, fitness club for free, etc. Working is also great. The large majority of people at CGI are very competent and motivated persons. As you will work on many projects in your carreer you will deal with many different technology, collegues. It is very pleasant to "change job" every 6 months. It forces you to keep up to date technologicaly and does not let you fall in routine.
Minpunten
Those are the downside of working in a consulting company. The biggest drawback is that between projects you can stay as long as 3 months without been re-affected on a new project. It is a good moment to learn about new technologies but that is pretty hard for ego since you may feel "unnecessary" for a couple of weeks. Of course you are still paid in the meanwhile ! The other issue is that you often change projects, so it is harder to develop social relations with your collegues, as teams change all the time, but nothing is impossible !