@Bytown rider:
We have the thermal glass on our '18 S, and would spec it again.
I wear hearing aids, and my wife had throat surgery and talks very softly, so it's helpful for us to communicate. Even I can STILL hear the very nice engine sounds and shift points when I floor the car, so it doesn't take that away. Additionally, it adds to the high-end environment, IMO; we also opted for full leather. We did not get the glass for its actual thermal properties, but for this noise reduction.
I've never owned a radar detector, so I can't comment on that. In terms of phone reception, I can't really comment on that either, because we have only one car; it seems okay to me.
I am still surprised that more folks who spend the extra money on Burmester (we have the Bose) don't go with the thermal glass, as well, as they invest in a superior audiophile environment.