So here is my impression and experience with the btunes unit paired with the bose qc25.

The device is fantastic! Build quality is excellent and should be included with bose qc25 from the factory. NFC pairing is fast and easy. I had it connected to my nexus 6 (lollipop and then marshmallow on project Fi) and with my macbook pro.

I could watch a movie/show, see that there was an incoming call, pause movie and pick up the phone call. After the conversation, I could resume watching the movie all while never having to remove the headset!

I did not experience any audio lag while watching/streaming music, tv shows, movies, anime, football. Sound quality was good, about the same as being wired but I'm no audiophile, so YMMV.

Range is a little better than my other BT devices (plantronics headset, generic wireless headset to use while on my treadmill) I did not test on plane yet as my scheduled trip/flight this month as been cancelled. However I can tell you that getting up and running to the bathroom without having to unplug/remove headset feature alone is worth the price of admission.

With the BTunes device plugged in, the bose qc25 does not have to be turned on and can perform as if it's was wired. May help if you forgot to pack an extra battery while on a flight.

Battery life was very good. I didnt time it but I spent at least 7 hours and it still says battery medium ^

Overall, the BTunes unit is an invaluable add on for your Bose qc25 headphones. It takes little to no room, can fit in the OEM Bose case and gives you wireless freedom all WITHOUT sacrificing sound quality, build quality and battery life.

I'll update this when I take a flight to see how it performs in the air and how the BT transmitter works with the BTunes receiver.