I've always found Google Maps' listings a bit lacking. For something that is supposed to map the world, it still won't show me all the restaurants on a main avenue in NYC[0]. It still doesn't pinpoint the right locations for some places and for others it simply can't find them. I think we're still far from the future of a 'one true map' that has it all, unfortunately. I still don't trust Google Maps to return quality…
That should change, according to Zagat (owned by Google): http://blog.zagat.com/2013/05/zagat-helping-you-find-excepti...
The biggest thing that Apple Maps has over Google Maps is their partnership with Yelp. Yelp is arguably the best source of business information in cities where it's available. It's up-to-date address-wise, lists pretty much every restaurant and attraction, has hours for many of them, and even menus. Plus decent reviews, and lots of them. Google and Zagat can't come anywhere close.