At least in terms of the service being cheaper in Canada, from what I've been reading, they don't have as large of a catalog. Lots of American TV is not available.
Plus, isn't Internet access more expensive with smaller caps?
This is very typical in Canada. The selection, not just of the Netflix catalog, but also the selection of products that one would like to purchase up here is very limited compared to America. And if you do find what you are looking for up here a lot of the time it is much more expensive. It's very frustrating sometimes.