The Road Tech 660 is the best deal, and I have tried others inc a TomTom and a magellan. The Road Tech has a longer warranty than the same model of Garmin and comes with the dealer database already installed. You can buy it @ 20% for $599, not $700 - $800.00. Comes with car mount and cable, bike harness and 110V wall charger and easily wires inside the fairing. Also it is water resistant, I have ridden thru some major rain without a single problem.
I don't like the center mount as shown above, it is to far from the rider and blocks either the radio or the gauges depending on how you mount it. For a RG nothing works better than the HD handlebar mount, for a EG type bike the fairing mount is very efficient. Both put the GPS close enough you can easily make changes etc without having to reach.