The $100 is worth it if you get a confirmed upgrade at time of reservation.

Failing that, I still have been batting 1000 on upgrades with Air Canada even though they waitlisted me on the return home yesterday for one of the flights. There were still several empty seats in business when the plane left even though they were showing no more upgrade space available. Check out the availability of J or C class seats on CP for your flight with EasySabre or ITN. Might tell you that you have a good chance anyway if you see availability.