The one issue with T-Mobile is it uses the fairly nonstandard 1870 MHz frequency
Actually, T-Mobile uses the AWS spectrum (in addition to PCS/1900MHz spectrum) which has the uplink around 1700MHz and the downlink around 2100MHz. AT&T and Verizon both have AWS holdings as well as Cricket, MetroPCS, and others. It's standard spectrum and MetroPCS and Cricket are actively using it for service today. AT&T and Verizon seem to be holding it to use for LTE in the future when increased capacity becomes necessary.
Actually, T-Mobile uses the AWS spectrum (in addition to PCS/1900MHz spectrum) which has the uplink around 1700MHz and the downlink around 2100MHz. AT&T and Verizon both have AWS holdings as well as Cricket, MetroPCS, and others. It's standard spectrum and MetroPCS and Cricket are actively using it for service today. AT&T and Verizon seem to be holding it to use for LTE in the future when increased capacity becomes necessary.
If you'd like to learn more about AWS spectrum and see some nice maps of who bought what, Phone Scoop has a great article: http://www.phonescoop.com/articles/article.php?a=99&p=14...