1. Limited distractions. 2. Traffic Lights, Stop signs are so easy to follow! 3. Lanes are rendered very clearly.
Of course, once in every other blue moon I have to open Google Maps when I find myself in an alley with no outlet, while Apple Maps is telling me to drive through the building.
The interface is really the best, but the route finding is the worst of any apps which I used. I had to go back and find a different route many times. And the speed limit was completely useless everywhere, random guess is better. Not that any option would be perfect, Waze and Google Maps have their own problems.
Also worked flawlessly in London across multiple transit modes (tube to thameslink, etc).
Driving directions have also been far superior at least in the way us Americans give directions (including quirks like “take a left at the second light” as opposed to just robotically naming streets)