— Besides public transit directions, Google offered options for avoiding tolls or highways while driving. It allowed me to choose continuous satellite images instead of animated maps, while Apple's app offered them only for route overviews, not for live navigation.
— While Siri's voice sounds much more human than the one Google used in its early mapping apps, Google now has a voice that makes Siri sound robotic by comparison. Google also was more sparing with words, which was good as long as I didn't get lost for lack of detail.
That said, Apple's map offers 3-D views. That may sound like a gimmick, but it presents the map in a way that mirrors what you're seeing through the windshield. On Apple's map, the direction you're going is on top in the regular view or toward the back in 3-D. Outside of big cities, Google often has north on top, which can be confusing when driving east or south.
Apple's maps are also more pleasant to view. Instructions such as "turn right onto Pearl St." are in white against a green background, similar to the signs you see on highways. Street names at intersections are in a green rectangle, similar to actual street signs at corners. Unlike Google's, Apple's app showed me the distance and time remaining and an estimated time of arrival all at once, though I would have appreciated larger text.
Apple's app was mostly dead-on in getting me to my destination. The one big miss was when it had a winery I was looking for about a half-mile east of its actual location. I went to another instead.
But Google has made mistakes, too. It told me to turn left to get to a lighthouse along the Straits of Mackinac connecting two Great Lakes, even as the road sign in front of me pointed to the right. Then again, Apple's app didn't even find that lighthouse in a search.