how well will it work in Canada?
I am not a Canadian, but I wouldn't count on the product working well, given that Amazon suppresses digital content to anybody they don't happen to care for. Australia currently falls into this category; digital copies of books are unavailable where Amazon is perfectly happy to sell you a dead-tree version.
I happen to prefer the latter, but for some texts, it would be nice to forego the exorbitant US freight costs.
To be fair, I really doubt it's that they have an axe to grind against Australians. More likely is some annoying conflicts with Australian laws, publishers, organisations and/or cell phone companies. It really wouldn't be a smart decision to not release content to Australia because a dingo ate Bezos' baby or he was molested by a Kangaroo or something.
Same as Canada. I'm sure they want to have my money, but are either waiting for our (terrible) phone companies to stop sucking, or some conflict with Canadian publishers or laws. (For all I know, my country probably has some law forcing ebooks to have 30% "Canadian Content" or something equally stupid.)