I upgraded my wife's phone with from iPhone 6 to iPhone 6s just for band 12 coverage since coverage is spotty at the outer fringe of suburbia. T Mobile touts the coverage 'all magenta' (at Gum Springs Rd/Sudley Rd zip 20109), but coverage is crap. There is no band 12 as indicated by the map, iphone 6, iphone 6s, and my LG G3 are all on crappy 2G (1 bar) and then searches for connection. The area I am referring to isn't out in rural country, and this isn't just one spot - I can document numerous areas. T Mobile needs to do a better job of providing seamless coverage where there is coverage, and stop using a 4 inch paint brush to edit their maps.