Having used a TomTom One XL for four years I decided it was time to update the maps. It had the whole of Western Europe but having paid an annual subscription I had to choose from three regions of Europe with the assurance that I could switch region at any time (provided I had an active subscription of course)
The first three updates went ok but on the fourth and final update the device no longer had enough memory to accept it. Complaints fell on deaf ears.
My advice is that updating is extremely expensive bearing in mind it is much cheaper to buy a new device every two years as critical changes in the road network don't happen that quickly.
Happily my device dropped to bits recently so I have now updated with a new device.
So don't update your device, buy a new one and thereby try other makes.