Kobo is where it's at in Canada. It's the most popular service here.
I really appreciate all the little changes and tweaks Microsoft is making to 8.1, however, there is something I find rather annoying: why does the Action Center always tell me that I need to make...
Is this going to screw something up for those of us (and I think this will be a fair number) who have Modern Mix installed?
I find it rather odd that you weren't able to find the 520 for Rogers in Toronto. In Hamilton, I was able to get one from Best Buy for $99.95. I highly recommend it as well.
I don't know about AT&T, but the 520 from Rogers in Canada has the updates.