I've been buying and trying different blutetooth stereo headsets supporting the A2DP profile, in search of the perfect one.  The form factor on this one is just about the best.  The dogtag chain relieves strain from the earbuds and can be hidden discreetly under your shirt.  The earbuds are designed to loop behind your neck, which is at first a bit odd, but makes a lot of sense.  The headset profile sounds pretty good and the A2DP profile is good but not excellent-- the bass is rather weak.  I pair with the Sony TMR-BT8iP on my iphone to connect to the A2DP profile.