I have been using the Scala G4 and like it with my Zumo/XM/Cell phone. Sound isn't the best for music, at low volumes anyway, but the phone and nav commands are clear as a bell. It works with an open face and even works with my full face using the microphone boom. I think both the Sena and the Scala offer a wired mic that can go in the chin area if the boom won't contort sufficiently. Both systems have been rated as the best currently available by magazines.