Having used a Windows Phone for some time before switching back to Android, the HERE maps app was the one thing I missed the most. Offline support is a must for me and Google Maps' offline 'support' is a joke. (I'm currently in Paris, without mobile Internet access. Google Maps is useless as soon as I leave the house.) OsmAnd/Maps.me do offline properly, but their UIs are lacking and both have serious GPS issues on my Nexus 5.
HERE just works great. There are many lovely little features.
Like, if I click on a subway station nearby, Google Maps (Lollipop) will show me the name of the station and how long it takes to get there, and if I swipe up it will also tell me the lines going from that station and show some share/depart buttons and street photos.
If I click on the same station in HERE, it will overlay the routes of the station's subway lines on the map so that I can at once actually see where they are going. Incredibly more useful, especially in big cities like Paris or Berlin where there can be a dozen subway lines or more.
I wonder if small features like these and the whole offline thing reflect where the developers come from? It seems like the Google Maps team doesn't take public transport very seriously, and that they can't imagine people ever being without Internet access.