I had been using the Shure BT-1 cable for about 3 weeks. Loving it. Pairing it with my iPhone 7plus. Playing music with itunes and downloaded hi res Tidal files. I had use it to drive Shure 215, Westone W10, Fenders Fxa5 and Mee audio Px (massdrop version) BT 1 works well with those iems and its near wired quality. Infact W10 seems to sound clearer using BT1. Even the hard to drive Px seems to be ok on it. Except the sound stage seems abit smaller for Px. I had tried BT1 against westone bluetooth cable and purdio 840. (Both with better declared specs like aptx etc.) Both cable lost to BT-1. The volume seems lower and under powered. And had to tune like max audio to drive a Px when using a purdio 840. While BT-1 can do it with like 60-70% when driving a PX. Overall i find its the best performed and best valued cable in the market. Note: i find the sound to be weaker when pairing with my macbook air. Guess having an older bluetooth player will affect the sound quality too.