We have a Nuvi 760 (iirc. Can't be bothered to go look!). I have been very frustrated with the inaccuracies in their Australian mapping. Whoever is responsible for it needs a BIG kicking 'round the back of the sheds!
For example, there's a number of traffic lights around here which have beenthere for years. Garmin thinks they're still roundabouts. BP Benowa is actually the Shell 1/2km up the road on the other side. The BP motorway services at Caboolture are 6km south of where Garmin says they are.
All a pain in the backside when you're on call & never been to one of those places. Finding even major supermarkets can be damn difficult or impossible as well.

I mean, come on! We onl have 20million people here, a far simpler road map than the U.K, France, Germany or wherever & commensurately few adresses. So how hard can it be to get the locations right!?!?

Yes, I would buy Garmin again when it's time to reach my current GPS. But in the meantime I do think if I've paid good money for their product, they can at least provide said product at a level reflecting their no. 1 position in the top end of the GPS market.