I just received my unlock code from AT&T for my Windows phone and unlocked it without a problem.
Using Calibre and Bookviser, I now have a great $29 reader with WiFi internet. The Lumina uses Windows 8.1 and its 1280 x 720 screen is great for both e-books and video. Being unlocked, it could be used with different carriers.
Doesn't get much better than this.
