Here is an audio example of the Jawbone bluetooth headset being used in conjunction with my Mac Book Pro while iTunes blasted 90db of music 6 feet away through my stereo.
It seems as though the noise cancellation needs a few seconds to settle, so its best to not start talking right away. Let the headset settle and then start talking.
Apparently my MacBook Pro sucks for bluetooth audio. Before you use this demonstration as an example of Jawbone’s audio quality for a phone, please see this post