So after using the new Bluetooth dongle quite a bit over the past couple of days, I can confidently say... it’s fine. It does what it promises. Battery life is somewhere around the 8 hours Beyer quotes, and the multipoint connection support is pretty nice (for me, it pairs to both my iPhone and my iPad, and switching between them is as easy as pausing on one and resuming on the other). To add to what MarkF786 mentioned earlier, wireless range is so so—I heard semi-frequent dropouts when leaving my iPhone in one room and walking into another (my apartment is very small, but yeah, walls). I could even get the connection to stutter sometimes when moving my Apple Watch between the dongle and the phone. Not a dealbreaker, but notably worse than the ES100, for example.
When switching over to a cable connection, the biggest difference is the change in volume. The wireless dongle is actually quite quiet, requiring me to leave the volume around 50% most of the time. When cabled, I can’t go much over 15% before it becomes too loud. Maybe that’s where Beyer found those extra hours of battery life. The actual sound quality of the dongle is fine, but dynamic range sounds a bit improved when cabled (subbass in particular becomes more present). Since I’m still acclimating to the Xelento’s (wonderful) sound, that’s about all I can say about audio quality difference between the included Bluetooth dongle and the cable.
That said, the ergonomics of the Beyer dongle are pretty bad. The cable isn’t quite long enough, so I frequently have to choose between clipping it too high (which causes the earbud seal to loosen and pop out), or just letting it hang (which pulls on the earbuds just a little too much). I’m definitely sticking with the standard cable and my ES100, because that combination is actually more manageable than the Beyer dongle (since I can wrap the full length cord however I’d like), the ES100 sounds better, and the standard cable makes plugging into my Switch or other devices pretty easy. So yeah, if you’re looking for a wireless option for your Xelentos, I’d either consider the Shure 2nd generation cable Mark mentioned earlier, or a Radsone ES100. Both offer better ergonomics, and the Radsone for sure offers better sound quality.