I have the SMH-10 but I use it mostly for my Garmin GPS. The helmet speakers aren't exactly music quality and are very bass shy so don't expect iPod quality listening. But I think it's a fairly good compromise between listening to Derek Trucks and hearing the truck that's about to run you down.
Kind of a funny story. I kept hearing this elevator-like "ding, ding" in my headset which I presumed was the Sena attempting to pair with another bluetooth transceiver in the vehicle next to me. I griped about this on another forum but nobody knew what I was talking about, even those with the same model of Sena + Garmin. Then somebody said, "Wait, did you install the Trapster update to your Garmin? If so, those dings are to warn you about reported speed traps."