Ive had XM on 2 bikes now for almost 70k miles and have been to every state west of the rockies including canada. First bike had the HK unit with the antenna inside the fairing, never had an issue unless I was under heavy tree cover or deep in a remote canyon. The current bike I have a Kenwood deck and mounted the ant on top of the inner fairing, it works well I suppose. As far as tone and sound being digital, really thats like sitting along side a airport runway and trying to listen to quality symphonic sound. For another $50 I could have got a high def radio, but you think in an open bike you will hear a difference? At 80 mph I can hear the music but it may as well be from an old transistor radio, its clear but hardly high end sound

 

I had one on my last bike. You will find the volume of that unit will be lower than that of the radio. You will be able to hear the difference when you switch the inputs. There aee no adjustments to correct the level. Not a big deal but noticeable. Others have said the same. I now use a small handlebar mount unit plugged in to the front of the radio. You can control the output and set it to the same volume as the FM radio or louder.

There are some advantages to an external. I have a GPS and a XM radio hooked up thru the radio. I use a box from www.cellset.com. The GPS and the Satellite radio plug into the unit. Whenever the GPS "talks" the music is cut off. When the GPS is done talking the music comes back on. Really cool passive device. It can be seen here: http://www.cellset.com/AuxSwitchSet2.html