I agree with the pro-F posters. The advantage of flying LH from YUL is that you probably won't be on a 747, which is arguably has the poorer of the LH F on-board experiences (16 seats arranged 2x2, which doesn't feel particularly exclusive when there are a lot of people in the cabin; the Airbuses have 1x2x1 and half the number of seats).

The overall experience is much better than AC business class.

Returning to Canada via Asia to try F on one or more of the Asian carriers is a good idea, if you don't mind the transit through the US.