Lol. I find it quite good and reliable with a good database of local amenties (i have the 2010 Europe disc map). i have google maps on my phone and a plug in garmin with live traffic. it also has the offroad DF and compass which the garmin and google doesnt have. Though, in surrey i'm not in the wilderness that much (only when north of toddington services).
The built in unit picks the same route as the garmin. it's not the most modern system in the world but its simple enough that the wife can use it both on maps and turn by turn.