Band 12 is rolling out pretty quickly and is spectrum that allegedly helps with a lot of issues caused by buildings / dense urban environments / long range / etc. I can't confirm personally since I don't own a device that supports LTE band 12 (purchased before TMo bought this spectrum....) but reports seem to be very positive.
http://www.spectrumgateway.com/t-mobile-700a-spectrum
Band 12 is rolling out pretty quickly and is spectrum that allegedly helps with a lot of issues caused by buildings / dense urban environments / long range / etc. I can't confirm personally since I don't own a device that supports LTE band 12 (purchased before TMo bought this spectrum....) but reports seem to be very positive.