I am really interested to see how T-Mobile Network Modernization works out especially with the iPhone running on T-Mobile 3G, HSPA+, and LTE. It will also be interesting to see how good is the voice quality if T-Mobile will offer Wi-Fi Calling on the iPhone. I remember when Sprint first released the iPhone that there were quite a bit of customers that experienced service problems with slow connections that made the data speeds unusable for some of them.