Your experience also represents the bulk of the problems I've had. I'm in the Chicagoland area, and the POI data and roads have been pretty good. But the search doesn't seem to prioritize nearby locations. If your search string exactly matches the name of some town, anywhere in the world, it tends to give you that result.
Echoes my experience as well. I searched for a nearby street and ended up getting the same street further away. It directed me away from Manhattan and into another borough.
And making up that 5% is going to take 95% of the work.
I was stranded at O'Hare earlier this week, and United put me up at the "Crown Plaza", according to my hotel voucher. I searched for "Crown Plaza" in iOS6 maps, and was suddenly transported to Vancouver. In Google Maps, it correctly surmised I was actually looking for the nearby "Crowne Plaza".
iOS6 maps is 95% as good as google maps, but the missing 5% really hurts.