I bought one to integrate with my 1500. It works perfectly and even has NOAA which is real handy. For my bike, it is a plug and play unit. I found that the volume knob did make contact with the windshield as my shield is from Show Chrome. I had to notch a section so that the knob would not make contact. When I did break the knob, J&M replaced it free of charge. I bought mine from Sierra.
I also had the same one on my GL1500. I got it from Sierra. It was a great unit for the short time I had to use it. Reception was very good, but I never had a chance to check on the distance. I would assume the generic handlebar mount unit would be of the same quality, except your headset would plug directly into the CB unit instead of integrating into your present system. Actually, I still have the CB, just no bike to put it on at present.
A friend of mine has a Honda Shadow 1100 and has tried the somewhat jury-rigged mounting of a handheld Midland CB with a power connection and a 4 ft. antenna. Doesn't work very well; he can hear me clearly from my Wing but all I get is gibberish from his setup. Thus the interest in the J&M setup and whether it is worth the major financial investment.