I'll be applying for McGill in the fall for the following fall. Luckily I have above the average that they require to get in (pretty much a 90% minimum - I'm 95.2%) as well as references, etc. (required for Education studies).
But about two years ago, I applied to CEGEP because I wanted to finish my "second school" schooling in a more mature environment. They accepted me and kept spamming my house with mail, even after I said nevermind because they were going to charge me wayyyy more than I could afford. The site said it was around 1,000$/yr with books, if I recall correctly, but because I was from Ontario they were suddenly charging me 4,000$/yr! So I stuck with the Ontario board and I'm glad I did. CEGEP would've taken longer and wouldn't have truly benefited me anyway, except unique courses like Arab studies, etc.
If you have the Ontario diploma, you can just jump right into university. Otherwise, in Quebec you hafta go Secondary->CEGEP (1-4yrs)->University/College. Kinda sucks. Figure I made the better, less time-consuming decision.