[rfranzq]

When one looks at the AT&T's Prepaid coverage maps, one sees very little coverage in the 'Far West.' Montana, Wyoming, North and South Dakota have almost nothing. Nebraska, Colorado, and Nevada have almost nothing except their biggest cities. New Mexico and Arizona are the same.
T-Mobile's Prepaid coverage map seems to have a lot of coverage but requires roaming and one needs to make sure one has a US dual band phone to take advantage of all the roaming.

SIMple Calling claims better coverage than both and now that it has dual [USA & UK] phone numbers and international roaming it might be a good option for those who need modest US/Canada rates and good prepaid coverage in North America. [I have seen others on the forums claim [which I have not verified] that the rates are cheaper than Canadian predaid SIM's rates in the USA. So the SIMple Calling SIM card seems
to be a good option for both European and North American users of prepaid SIMs.

I will post below some coverage reviews in different states & hope others can add to it.

My nephew is on a road trip to South Dakota from Los Angeles and will investigate for me how two SIMple Calling SIM SIMs do in the hinterlands. Which networks besides ATT and T-Mobile will be a major focus.

Happy Roaming!