Well it certainly looks pretty cool.....
However I have a Zumo 550 which I am not overly impressed with - it locked up twice yesterday when using it in my car, for example.
It also failed on me last year, the 1 and only time I used it in the rain on my bike - despite supposedly being waterproof! The cradle somehow broke due to the rain - Garmin replaced it for free which was good, but still it shouldnt have happened. One of the reasons I went for the Zumo over a TomTom was that it claims to be waterproof!
I don't know what the improvements are on the 660, maybe they are better. There are also several VERY satisfied users of the Zumo - there's a dedicated forum for them!
Although I have no plans to replace the Zumo, when the time comes I will certainly look for an alternative to Garmin.
In fact, Becker have recently announced a motorcycle system so it's not only TomTom/Garmin now - no idea what it's like but seems to offer 3D mapping which looks pretty cool (unless you live in the Netherlands......

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