Ironically the booster that T-Mobile provides causes more issues. Unlike the old ones that brought the signal in from an antenna to the base using some coax, the current models link up the receiver to the amp using unlicensed 5GHZ. This killed my 802.11ac speeds when I had one.

T-Mobile will now send a full femtocell that uses your ISP's net and broadcasts both WCDMA and LTE. It's much better.