I have 5 GPS units, all Garmin. A couple of 200's, a 500, a 2620 and a new Road Tech 660. Bought the Road Tech unit because it was cheaper than the Garmin unit ($599 thru Jenni and had a $100 rebate, which is no longer available). The Harley handlebar bracket works great, I had mine chromed although you now can buy a chrome one. Wiring was simple, it works great. The lane view deal is a big help in strange cities, just an exceptional unit.
I use a Scala Headset with bluetooth for intercom so I am able to get the commands thru that which works exceptional. Just very pleased with the unit. It came with a car mount and now when I want to use it, I have to get it from my wife's Escalade as she is trying to take it over because it is so much easier to use than the factory unit.
I strongly recommend it (or the newer 665 which has XM and weather). I already had the XM unit on the bike so I went with the cheaper 660 but weather add-on is very hi-tech and saves using the droid.