Fitting to my bike was very easy as I already had the ram mount I used for the 500 and I only needed to put a plug onto the power lead and it was ready for action. Unlike the 500/550 there is no security screw on the cradle which makes the 660 quick and easy to remove - too easy for the light-fingered.
The display is crisp and bright and shows as much detail as I need on a journey. On it's first trip out it surprised me, with a detailed and almost photographic rendering of an approaching junction complete with accurate roadside signage; a vast improvement to what I had become used to on my previous model. There should be no excuse for being in the wrong lane at a complicated junction now.
The PC software included in the package (MapSource) I have been using for a number of years and is the backbone of my route planning. Downloading routes and way points to the 660 is still as easy, though it was here that I found the one thing that will bug me - you have to remove the battery cover to access the USB port.
I have only had the 660 for a few weeks with few opportunities to use it but I think this is going to be a very useful navigation aid that is easy for a motorcyclist to use.