You're counting the months of employment experience, but you're omitting other things like the amount of interview experience (six co-op cycles means six times to get an interview at Google, Facebook, etc.) and opportunities to refine your resume.
The shorter employment cycles also provide an opportunity to try different "styles" of company to see what you like best. Throughout university I've been employed in government, at a multinational corporation, at a startup of nine employees, and at the company I cofounded. This experience, combined with living in different cities (Ottawa, Toronto, Vancouver, Waterloo) for each, has been invaluable.
This. I can't tell you how useful it is to have learned to be completely comfortable doing interviews. Through my co-op experiences, I've probably done 25 to 30 interviews at all sorts of companies, and different styles of interviews. And all this before I graduated. Very useful!
These factors are really where Waterloo shines. At my school I had 3 6-month internships so I got just a taste of those things I think; more chances to interview and refine would have been great.
