I'd tell you to use Here in Europe and the US, and Google Maps outside of those regions.
However, the quality of Here has been improving, so we'll see.
Here Maps I can use offline. Here in the UK they seem to be accurate, although they are still at least two years out of date in some parts of the UK (Margate, for instance).
Here maps is a good choice, but it also depends on location. I also use copilot and find it even better than here maps it gives alternate routes but it's not free.