It varied. The biggest difference is the Canadian interviews covered a lot more ground and asked very specific, fact-based questions. I interviewed for a bioinformatics research position at some podunk Sunflower genomics lab at UBC, and their several hour long interview consisted of questions that went pretty deep on C++, Perl, Linux sysadmin stuff, and molecular biology, and was followed by a round-table interview where ~15 people grilled me on like, BS HR stuff (stereotypical "give us an example of how you used conflict resolution in the workplace" type questions). For a position that paid around $40K! That's probably the toughest interview I've ever given. It's mind-boggling that they are able to hire people, in retrospect.
Thinking about everything else said in this thread, I think the type of interviews these companies do sort of make sense. After all, all the good talent that knows its own value is already gone; all that's left is a mix of the incompetent and the undervalued, and they're trying to pick out the undervalued.
That requires a lot more rigour than the US process, which basically consists of "hey, we're offering [huge salary], compete for it."