After trying a few other bluetooth headsets I knew I wanted one that had really good noise cancelling ability. This one does it. (I cranked up the tunes in my car and carried on a conversation as a test - no problem).Big but comfortable behind the ear (I wear glasses too).The small power/mute button is annoying but manageable.My only complaint is with Treo because they don't support the playing of music to bluetooth devices... (yet)