This review will only take into account my views on the usefulness of the maps and my experience of using it in the UK.
The software is very simple to use and the directions are clear. They are given in good time and repeated as you are just about to do the instruction. In the event you dont understand the instruction or do something unexpected you will be redirected back to the place where you started and then if you still refuse to do as the instructions the map will be recalculated based on your current location. It is therefore very adaptable.
The actual maps I have used have been very detailed and fairly up to date. The one thing I did notice is things like speed limits and speed camera locations are not as up to date as the actual street themselves. I never really came across places which the maps did not know about and if I did the software managed to over come it without too much fuss.
The graphics are nice and clear so you never have to look too hard at your unit and street names and one way signs are explicitly shown. In many ways the maps on the system are easier to read and understand than old paper maps but also much more expensive