I'm generally disappointed with the music playback on the Dual, either with the supplied headphones, or with my Jabra BT620s.
Pressing play on the Jabras doesn't always make the Dual start playing. Sometimes pressing play on the Dual, playback commences through the phone instead.
The momentary pause in the music seems to be a "feature" of the Dual though
It does it both via wired and A2DP headsets.
Also, see what happens with incoming calls when you've got the bluetooth headset connected. Mine routes incoming calls through the phone, not the headphones.
And for those considering the S9HD - consider the price difference, and look at installing the SRS WOW HD software onto the Dual - probably does a similar job.