Overall I am really impressed with the coverage that I get with T-Mobile particularly in the cement bunker that is my high-rise condo. It was the same coverage that I got with Sprint until 4-5 years ago when Sprint decided to thin out their macro sites and replace them with mini macros, hence my Magic Box. I have disconnected the Magic Box. I now get great signal by my bedside which is for some reason a dead zone for Verizon and AT&T. I have been parked mostly on B4, occasionally on B2. Have not encountered B66 yet.
Now I would like to eventually have my T-Mobile line part of an e-sim.