I hate this airport! It is inefficient, badly organize and the transport links makes Montreal looks worst that developing countries.
It seems that the security and Canadian customs are managed to optimize their own resource without the slightest care about the passengers.
Seriously, they made a big investment on the building in the last few years and expanded Canadian custom hall quite a bit... BUT they don't staff it. Schedule plane service landed every day about the same time, can't you staff the place so people don't have to wait an hour or more for immigration? Apparently not. Canada is also the only place I know where citizen and permanent residents don't have a priority line (you know because citizen can be cleared faster and you can clear the place?).
The train line that go to downtown is less than a mile away, but there is no convenient train services to downtown and they have been talking about a rail link to the terminal for over 40 years... nothing
Can this place be made efficient and serve it's function well? Yes. Does it do so now? No, absolutely not.