The one knock I have with the X3 is the instability of the Bluetooth. It seem to flake out sporadically and if I put the phone in my back pocket when walking. The sound is good but unstable. Hopefully it will be addressed in an upcoming update
I have not had any stability issues with BT so far. It did take a while to figure out where the NFC hotspot was when trying to pair it with my JBL powerup. Found that the hotspot is near the middle of the back cover. I am hoping that with updates the rough edges of usability will improve. But, WOW what a high quality device!
Now I have found the music controls via Bluetooth do not function with the same headset that they did work with a few weeks ago. This is moving in the wrong direction