Google Maps in Japan is unusable. Many times it directed me which might have been the shortest way but through micro-streets that are really difficult to navigate instead of the more efficient 2-lane.
Unfortunately it usually ends up being slower, because the tiny road aren't faster, Google just has very low accuracy speed data for then.
Apple Maps on the other hand tends to prefer simpler routes with fewer turns. In London this means Google will take you down a maze of backstreets, which frequently have turn or modal restrictions (specifically put in to prevent Google Maps style navigation) Google doesn’t know about. Whereas Apple Maps tends to stick to main thoroughfares, which are always quicker and much less stressful to use.
For me the classic example is driving from east to west across London. Google maps will insist on taking the wiggliest route that’s entirely 20mph speed limits. Apple Maps will suggest heading out east to a ring road and looping back west to your destination. A longer (slightly slower) route, that about a billion times easier to navigate.
I've been trying to move to OSM but so far i haven't found any usable alternative that actually gets and has good coverage of Japanese addresses in Kanji/hiragana as well as romaji. Apple Maps is way behind Google here (and I find Apple Maps otherwise quite usable in Europe).
Apart from in-car navigators (with terrible UI, at least the ones I tried so far) I'm not aware of even domestic alternatives that are usable. All my Japanese friends use Google Maps.
IMO, best dataset at the expense of a very Japanese-style UI.
It goes to show how these companies are much less monolithic than we might sometimes assume.
There is one time it really screwed up. I like walking along those micro streets, lots of interesting stuff to see in neighborhoods. My wife and I were pushing out baby in a stroller and Google maps route sent us along a path that included a giant steep flight of stairs! It wasn’t a big deal by there was no mention that the rout would be in accessible to people who couldn’t climb stairs.