Pros
CGI has a decent work from home policy and a flexible work schedule. If you are in the right location, Fairfax or another major center, are highly political and you are willing to switch project a lot then CGI can provide a decent career path. CGI is a decent company for new college grads to get that first 2-5 years of experience before moving on to a better paying company.
Cons
The biggest complaint about CGI is the low pay, from my experience CGI pays in the lower 10% of the pay scale. The next most common complaint is the poor health insurance. CGI is a sales organization that happens to sell IT services and the company is structured around that purpose. Everything is about getting the next contract, not about creating quality products. So you will be pushed to complete work as fast as possible. One of my biggest complaints about CGI (beside poor pay) is the lack of career growth within the company. Since CGI is a consulting company they hire most employees for a project, when the project is over CGI gives you approximately a month to find another project or they lay you off. Unless you're willing to switch projects often there is no long term employment stability at CGI. Mostly management is clueless and more driven by getting their next bonus check than insuring the customer receives a quality product.