Here's a quick overview of how Garmin GPSRs and cartography products work:
Garmin divides the world into 2 halves - the division is made about through the middle of Greenland. The North American half is referred to as 'Americas', and the European half is referred to as 'Atlantic'. For purposes of this discussion, I'm going to ignore Pacific region products.
All Garmin GPSRs will have a basemap loaded in them, it will be either an Atlantic or Americas basemap. Further, when you buy a new GPSR, it will come with CD's providing detailed cartographic coverage (street level coverage) for the appropriate geographic area - North America or Europe. In other words, you get the basemap and matching CD's included in the purchase price of the GPSR itself.
If you buy a GPSR on the 'wrong' side of the ocean, then you will need to buy cartography for the 'other' side of the ocean. This is expensive, in almost every case, the total cost will be greater than the cost of just buying the appropriate GPSR for the region that you live in.
The only time it makes sense (for a European) to buy a GPSR in America is if you think you will spend a significant amount of time using it in America. In that case, you buy an Americas GPSR - which gives you the Americas basemap - and then you buy European cartography as an additional purchase, probably for a cost of about USD $600 or so. This is what I have done, but I am a bit of an oddball, I live in Canada but work (and ride) in Europe.
If you plan to use the GPSR only on one side of the Atlantic, then buy the model (Americas or Atlantic) that comes with the cartography for the region you plan to ride in. That is both the simplest and (when everything is added up) the cheapest way to go.
Michael
