I just got the bt20s mmcx version and paired it with the Smabat ST-10. I am still getting the hang of slipping them on properly.
When they are on though they are extremely comfortable, I never want to take them off.
The sound though is less clean than it was on the es100 both on aptx...I guess that is too be expected, but the bass seems less fast and the separation is a tad less good. Mids seem more forward. It might be the snugger fit that it creates, or maybe the positioning blocks the port a little more...I am not sure but I will try it for a week or two and switch back to make sure it is not just in my head.
It had a teeny bit of white sound, but it is really minimalistic with this combo, you have to listen to audio books to notice, and even then it is not distracting.
The thing that irks me though is that the led light is always blinking, even when playing music. Your ear blocks about 90% of it, but in a dark room my wife still gives me a hard time about it. I might try flipping the earphones so the light points to my head see if the buttons are still usable, out but done light dim stickers for these bad boys.
Overall a pretty neat gadget, kind of a hybrid as they sound better than most true wireless sets I have tried but are ever so slightly less convenient without auto connect out of the case and fishing too get them on and off. Still on the fence if I will keep using them or just get a proper short cable for the ST-10 to use on the es100.
In that case the only mmcx I have to pair them with would be tennmaks pro and I don't see that sounding great...
Maybe the Nuarl is on the same level for sound or higher depending on what I'm listening to though with aptx.