I've read that Sony's new 910 (WH-H910N) has the same noise reduction chip as the XM3, uses BT5, and has a much more neutral sound. Still not able to easily switch between devices though, although it can (apparently) connect to one device for music and one for calls.If the Sony’s didn’t have that horrible bloated bass , they would be an amazing package.
I almost bought a pair in a one-day sale here, but returning would be difficult and I've not read any in-depth reviews yet. It's the new tech in the 25mm drivers (as against the 40mm drivers in the XM3) that I need to read about before buying.