I still use Map's, or a computer print out from Street Maps, and never been lost........

I love looking at maps. But rarely carry one in car, or if I do, its under all the luggage!.
I use Satnav all the time, even on destinations I know. Rather than keeping an eye on roadsigns and thinking about where to get go, it allows me to concentrate more on driving. Its a laziness thing. I know other people get distracted by it (inc Mrs TheBoy, hence another buckled wheel on MV6 last year coming back from Drax

)
Started using TomTom on my PDA around 2003 - imho was the best portable device then, and still is now. Running on PDA gives more flexibility than the standalone units due to the better POI add-ons.
BUT, and its a big one, it is utterly reliant on satellites. Absolutely bloody useless in the centre of the big smoke - lack of satelites makes accuracy poor, and it frequently has you on adjacent road. Birmingham inner ring road is another it has let me down on. Forest of Dean, well, nearly threw it out of window.
The factory fits do not suffer this problem, with primary (on Carin, Secondary on Siemens) location being determined by vehicle speed and changes of direction.