I've got the 660 garmen but I believe the 550 is a better model having used the 660 across Europe .
I also back up with a iPhone using the IMAP (Maps) app installed in route mode with data roaming on. Set price European contract through Vodafone (I think Orange is slightly cheaper)
With the iPhone it's highly accurate and has provided excellent service right across Europe and the USA without needing extra database updates..
http://motoplaner.de Is a fantastic site to build your custom routes for the Garmin - convert the route into useable file as then download them into the Garmin. The site is German but has an English language option but is not user friendly on iPad truely fantastic on a laptop or PC
My friend uses the 550 and it doesn't suffer from waypoint refresh reloads every time you move onto the next waypoint like the 660. The phone doesn't do any of that, it just simply re-routes if you move off course otherwise it's continuous map. - need to maintain phone charge though.
Ultimate additions also provide the waterproof case and power leads needed for motorcycle/M3W use of the iphone
