RE: Montreal Exchange sucks big time!!The "minimum guaranteed fill" rule is out the window now. I experienced it first-hand and got screwed. In order to get your fill, you should know the depth-of-market or at least hope that the asks are coming down to you and not moving away.
Here's a document explaining the "New Market Model":
https://www.boursedemontreal.com/circulaires/circular187-2001.pdf
Tradehappy :)