T-Mobile is started introduced in USA in 1999, that where network is going keep growing and spread over most part of USA in next decade or so. Cingular and Verizon aren't work if when people that who trip to Europe (such as UK) but T-Mobile is work so well in most part of Europe. I have no problem with GSM when visit in most part of California except for rest of Inyo County (that where Death Valley is located). If I'm from Canada then I will switch into Fido, that where there's SK2 and soon be SK3. 
T-Mobile is work so well when visit in Mexico and Canada, also some in other countries, such as most part of European Union.
