I think of Apple Maps the same way I think of North Korea's missile program: I know it exists and it has continent-level accuracy.
I use it all the time. In Portland it is as good as GMaps is at navigating fastest route during heavy traffic. Which is to say, not perfect, but adequate. It has yet to take me to the wrong location.
Yesterday I was trying to remember if this deli was on Howard or Folsom (and I forgot the exact name). The search results for 'deli' were basically everywhere on North America except for where I was (including across town). Searching for businesses with Apple Maps is nearly impossible, and the insistence upon installing the Yelp app to get more info is just infuriating.
Edit: Oh yeah and it can't find Grainger in Millbrae to save its life. Shit happens and business info is one of the hardest parts about mapping. Unfortunately Apple makes it damn near impossible to report problems to a real human.
Edit edit: My all time favorite though was asking Siri for directions to some club that I usually take BART to. I kept getting directions to a not that nearby and not that similarly named bail bondsman.