Until the Kobo is released and really reviewed it is hard to recommend it. If it works well then there is no way I would recommend a 5 inch screen Sony 350 over a similarly priced 6 inch screen Kobo Touch with WiFi. A smaller screen and no conncetivity vs more screen and conncetivity for the same price?
Kobo seems to have done very well in Canada. I would guess that the number of books available to Canadians through Kobo is the same available through the Kindle. The same geo restrictions will be in place. Amazon has a larger store if you are willing to pretend to be an American and use the US based book store.
I would say go with the Kobo (pending reviews) if you want a touch screen. Heck, if the Kobo has the same functionality as the Kindle than go with the Kobo even if the touchscreen doesn't matter to you.
If the reviews of the Kobo Touch are poor, I would go with the Kindle. It has great functionality, a great book store, is easy to use, and is reasonably priced.