Also keep in mind that T-Mobile's rural coverage has been rapidly improving, especially in the last six months or so. Northern Michigan (north of a line roughly

Also keep in mind that T-Mobile's rural coverage has been rapidly improving, especially in the last six months or so. Northern Michigan (north of a line roughly from Muskegon to Bay City) used to be exclusively AT&T roaming coverage, and further south there were some large coverage holes with no service (e.g. around Hastings). Now, almost the entire Lower Peninsula is covered, and the few remaining gaps are being filled in. A big reason for this, in Michigan at least, is that they have a chunk of 700 MHz spectrum; this is what they term their "extended range" LTE coverage. In Illinois, they don't have any 700 to speak of, but they're still building out new coverage in places where there was only roaming (such as the Macomb area). Their joint venture in Iowa (iWireless) is also lighting up LTE on their network. I've also run into brand-new coverage in western Indiana. They clearly want to cut AT&T roaming to the barest minimum. In areas where T-Mobile has 700 MHz coverage, you'll need an up-to-date handset to receive it - something you should consider if you were planning on switching an unlocked phone to them.