Problem with Apple Maps is that it's a no go on Android. Although, for major cities, as long as you have the coordinates of your destination, Google Maps works fine, for the most part. But they still haven't updated the maps data for the northern part of Kaifeng for example, despite me complaining to them about it multiple times (there are literally streets that have existed for at least 2 years but are not on the map).

As for transit directions, I'm not sure why it's necessary to have some app telling you exactly what train to get on. This isn't the US, where trains come every 15-20 minutes if you're lucky and 30-60 minutes normally, and trying to transfer at the wrong spot can add 30+ minutes to your journey. It's China, and the trains come every 3-5 minutes, so just look at the map of the metro system and use common sense about where to transfer. As for buses, even in the days when Google Maps would give limited information about buses, I never trusted it enough to rely on it. Always verify your map information in China so you don't end up choosing a hotel on the opposite side of the river in Shanghai from where your office is (my friend who works on Google Maps heard about this one for an entire weekend trip we took and I never stopped complaining about it the whole time).