Diesel Benz
MB Enthusiast
installed flawlessly on my 5800
the GPS positioning doesn't seem to be so well calibrated as it does with Google Maps (also free) but it's close enough.
Google maps pinpoints my home location exactly - it can even differentiate between the rooms in the house, if I move, my location changes. Ovi maps classes my 'home location' as next door but one. It's post code correct just like our Garmin unit is - I presume that this is because it is sharing the same software
The position does not come from Google Maps or Ovi Maps but the GPS receiver on the phone. But at least Nokia Maps used to put you to a nearby road, closest to the real position. If you take the positioning (simple) application from the phone, it shows the exact position from the GPS receiver.
At countryside I've had Nokia maps show me on a road 200 metres away when I'm off road (not with the MB).