I use a Sirius Starmate on my Cortech Super Mini tankbag. I runn a Motocomm headset from Radiogadgets.com so I can use my GMRS radio too.
I've used a wide variety of comm systems on different bikes. Bottom line is you get what you pay for. The Baehr, Autocom, Starcom, and J&M units will outperform the Chatterbox and Nadys of the world but their price reflects it.