I have used the N7 when I went to France. I downloaded FREESAT and the map pack for France.
I used WIFI when I put the address in. However, if you use this app please remember that you have to download postcodes seperately.
However, this App DOES recalcualte routes on the fly. I know this as I frequently took the wrong roads and it recalcualted on the fly.
The app and N7 worked well togethor (until the N7 broke). There is voice too.
Only slight issue with it is that it seems to favour main roads, like motorways, even if there is probablya quicker route. I tested it my home town also before relying in it in France and would often take very strange and convoluted routes when there was a road straight to destination.
However, for big journies it is excellent IMHO.