My BTR1 arrived yesterday. So far, so good! I bought it to pair with my Pixel 2 as an alternative to using the audio dongle. The BTR1 sound quality is very nice ... clean, not too bright, not too bassy. Plenty of amplification for a lower-impedance headphone. Spotify streams at "extreme quality" are very enjoyable, and sound particularly good. MP3s, in general, seem a bit muddy and I haven't figured out why (possibly due to conversion for BT?). Some very low hiss/interference noticed before starting music. I can walk around the first floor of my house and not lose signal when unit is clipped to my shirt, but receiver seems to need a clear path (I hugged my wife and lost signal momentarily). I might comment more when I've had a chance to use this unit when out and about, exercising, separated by longer distances from source, different file types, etc. All in all, a big step up from a typical smartphone headphone jack, and very convenient to use. Lacks the depth of my computer's soundcard, but I bought this for casual use. Seems leagues better than my old E06 Fujiyama. I'm pleasantly surprised for the price. EDIT: Earlier, I wrote that my se215s sounded muddier than usual using the BTR1. I went back and listened with the se215s, ie80 and Amperior (same tracks), and this is not the case. I think what I'm noticing is that most tracks on Spotify at "extreme quality" sound better than my MP3s encoded at or near same resolution (LAME). I am not technical enough to account for this. Could be my ears today, the quality of the encodings, the BT conversion, or that the amp/DAC is good enough to reveal things I wasn't hearing when listening to these tracks on my old smartphone. What puzzles me is that the differences seem greater than when I listen on my ASUS STX, which is pretty decent as consumer/prosumer soundcards go.