Arg - nothing like botching terminology to anger the engineer.
GPS is shorthand for a bunch of satellites that can tell you your position on the globe with unparalleled speed and precision. GPS is absolutely one of our greatest inventions.
GPS simply tells you that you are currently at Latitude 39.2707, Longitude -105.9821.
Now what you do with that position is up to you.
If you want to plot that position on a paper map - wonderful!
If you want to plot that position on a SOFTWARE map - be it GPS Receiver, or Laptop Software - awesome!
Accuracy of the map - has zip, nada, zilch to do with GPS.
For those of us in the States, there are a only a handful of companies that make maps. Everyone buys/leases/licenses those maps for their software and for their paper maps.
Like someone else has pointed out - if your GPS Receiver gives you bad directions there are at least two culprits: the routing engine and the mapping software.
Impugning GPS - the satellites - is grossly unfair.
I'm a map-aholic. I have several GPS receivers, and a raft of paper maps. Including TOPOs on a spare portable hard drive.