Andy in Sig said:
My bottom line on this would be, can you get 1:50,000 mapping for anywhere in Europe for it?
No, it will use Garmin Mapsource data just like all the others.
Garmins display vector data - lines joining positions defined by coordinates.
1:50,000 data like memorymap is raster, which is a picture just like a photograph or a scan of a paper map.
Raster maps just aren't suitable for use on a GPS that may be required to hold data for large areas and be displayed at a wide range of scales
Vector data can be drawn at any size without loss of information.
The only limiting factor is that things get too small and crowded together if you display too large an area on a small screen. This can be overcome by turning off irrelevant detail, so you don't have residential roads and small lanes shown when you are looking at a scale suitable for planning a route between towns.
Raster data is just coloured pixels, lines only existing as pixels of the same colour next to each other. You can see all the information at a zoomed in level, but as you zoom out you end up trying to fit several map pixels onto one screen pixel. All you can do to decide what to show is to look at the colours of the (eg 4) pixels that make up the single screen pixel, so if 2 are blue and 2 are white, you pick blue, but if 1 is blue and 3 are white, you pick white. Once you've zoomed out too many times, the white background ends up dominating and lines break up.
Looking at MemoryMap on my PC, at maximum zoom 1 screen pixel = 1 image pixel, and is 5mx5m on the ground, with the 1km grid lines appearing about 10cm apart. Each time I zoom out, 4 pixels are merged into one and the apparent distance between grid lines is halved, with 5 zoom steps until the grid lines are about 3mm apart. By this time anything that was originally narrower than an A road (16 pixels wide) has pretty much disappeared.
Using MemoryMap, you just switch over to a separate set of maps (1:250,000).
To view raster data usefully at the same range of scales that you see on a GPS, you would need about 4 separate sets of maps - eg 1:625,000, 1:250,000, 1:50,000 and either 1:10,000 or possibly 1:25,000 (based on OS scales). A 20x20km jpeg of 1:50,000 is about 7 Mb, 10Mb if you store the pyramids for multi-resolution display (4 pix -> 1) rather than trying to do it on the fly. 1:25,000 will be 4x that per sq km. If you start adding up what's required, you end up with about 1.25 GB for a 100km x 100km area, which is about the smallest area that would be useful for cycling.
Contrast that to the Garmin vector data, where you can get the whole of western Europe in the same amount of storage.