Amongst adcoms, there really isn't any benchmarking going on comparing Canadian vs. US universities. It's apples vs. oranges really.
Traditionally speaking, at schools like HBS, Stanford and Wharton amongst the Canadian kids the McGill and Queen's alums tended to be overrepresented (around 30-60% or so depending on the year). Not sure if this is a recognition of their pedigree by the US adcoms, or whether it's because these two schools tended to be the few (if only) schools where the banks and consulting firms don't limit their recruiting to commerce grads but would open up their recruiting to arts/sci majors and engineers (like their US counterparts, there's a lot of Canadians who were bankers/consultants pre-MBA). Keep in mind that relatively few Canadian commerce grads (whether its Ivey, Queen's, Laurier, UBC, McGill,etc.) bother applying to an MBA. Of the top of my head most of the Canadians I knew were arts/sci or engineering guys.
In any case, if you really are curious, I do find it amusing that Canadians have an inflated view of their universities' pedigree vs the top US universities. The Canadian system is great as a whole. But they simply can't compete or compare to the resources that the Ivy League and other top private schools like Stanford and MIT.
A more accurate comparison (if you can make a comparison at all) is that the Canadian universities are similar to the top US public universities in terms of resources and reputation. Schools like McGill, Queen's, Toronto, UBC and so forth are more comparable to UCLA, UC-Berkeley, UT-Austin, Virginia, and Michigan.
Ivey undergrad may be hard to get into, great for Canadian recruiting, etc. but if you are really talking about renown outside of Canada, the only university that has it is probably McGill. Queen's undergrad for example is one of the most exclusive and hardest to get into, but its reputation outside of Canada is still behind McGill or even Toronto.