Received my 1520 today as well. I was grinning from ear to ear. The courier driver couldn't believe how fast I answered the door !
So activated the Nano SIM from Windmobile I bought the other day (took two minutes). Then popped it in, turned on the phone, and Spanish ! Good thing I know a bit of Spanish !! I set the phone to US English, Region to Canada, phone re-booted and everything works !!!!
No issues with tethering or anything. I'm on a $40/month unlimited everything plan (includes North American calling, global texting, etc), so I'm set with this new toy for a long long time !
I have everything running perfectly, Facebook, Instagram, Lync (office connection), Skype, work email, Hotmail, Gmail, OnStar App. Battery is almost out, but it wasn't fully charged to start with and I've been using it constanly. Will give it a full charge tonight. the screen is just awesome and the pictures are fantastic. Now waiting to get a case, memory card, and QI charger pad (all ordered).
Let me know if you have questions, I'll try to answer quickly.