Great in theory, execution lagging.
The #1 downside that makes this almost unusable is that it shuts down in the background way, WAY too easily. Switch to the music app and chances are it'll restart, losing whatever equipment you were on at the time. The recovery ability is not good enough. And it's not a hardware issue; this is on 14PM, with background app refresh on. The SW team needs to improve app and activity persistence and this will be great.