It was 25% off before the the early 2017 price hike. So a little better than 25% off current prices.
I don't have all the numbers in front of me, but based on some scribbles I made when I was trying to figure out what I wanted to buy, I believe the 5-day base ticket was $271+tax, and the 7-day was $295+tax. Those were the adult prices. The child prices should have been about $15 cheaper, but I don't have the exact price.
Of course the "cost" of the Air Miles tickets will go up once the Canadian Resident tickets run out. Whether they are better or worse value remains to be seen. We know that Air Miles did not pass on the whole discount when the Canadian Resident tickets were introduced. If memory serves, the number of Air Miles needed for a discounted ticket was around 17% lower than the regular tickets they offered previously. So there is a small possibility that the new tickets (when and if they are offered) will actually be better relative value than the Canadian Resident tickets. But I wouldn't hold my breath.