Turn by turn is completely separate from the complaints about Apple Maps. I'm sure they work great, provided that your destination is plotted correctly in their database.
As for edge cases, that's the point. You have to be able to trust a mapping application with areas which are unfamiliar to you. A maps app can only be useful if there's a high level of trust, and when you immediately see errors in Apple Maps (some of which are clearly the result of overzealous automation, like labeling "Airfield Park" as an actual airfield) that trust vanishes fairly quickly.
As for edge cases, that's the point. You have to be able to trust a mapping application with areas which are unfamiliar to you. A maps app can only be useful if there's a high level of trust, and when you immediately see errors in Apple Maps (some of which are clearly the result of overzealous automation, like labeling "Airfield Park" as an actual airfield) that trust vanishes fairly quickly.