Thinking about the coverage of OSM I have just looked at the part of Spain where I will be going on holiday. No OSM coverage apart from main coast road. Looks like I will be buying City Navigator.
My pal is a bit of a technical novice and just follows tracks, so I think he will be OK with the OSM maps. I have been nervous routing with these maps since the last time I tried them for routing I only got about a 50% success rate. Them some of the routes were way longer than they should have been, like double distance.
BB