Basically, it's that she works great if you don't use her as a substitute for knowing roughly where you're going. You can't follow her instructions mindlessly but she sure helps me get around, even on semi- familiar turf. I'm learning the names of local streets I only vaguely knew and every so often, even when I know how to get where I'm going, I ask her to plot a route and it's sometimes a clever suggestion.
“news from me: Heeding Henrietta [1]”
This reminds me of an incident that happened over a year ago [2] (obliquely referenced as “Gregory started to drive, but wasn't feeling all that well, so I took over for him”) dealing with a GPS (Global Positioning System) (and Gregory and I have been over this incident many a time before, and I doubt we'll change our respective minds on the situation) but yes, I can agree that GPS works best if you don't slavishly follow its directions.
Then again, I can say the same thing about using computers too.
[1] http://www.newsfromme.com/archives/2007_06_30.html#013655