Apple maps in iO6 is seriously bad. In Australia it has some towns over 100km out of position. It wanted to locate my house in a different country and I just tried to get directions to my local airfield and it shows a route about twice as long as it should be. Seems it doesn't know about some major roads.
If you use Google maps at all DO NOT UPGRADE. I did the iPhone, but there is no way I'm upgrading the iPad.