The beta phase will run until July. Afterward, you can decide if you want to pay for the service.
However, the several T-Mobile users we know aren't bothered when they don't have signal ... at Verizon's coverage where you live and where you often go on the Verizon website. The map will also ...
Though reports on DownDetector only indicate the location the report has come from, and can't be used to give an exact map of where ... most of which use Verizon, AT&T, or T-Mobile's service ...