I like OSMAnd for it's ability to work for almost any purpose you need it to serve. Besides that I enjoy Magic Earth (on Play store) as a Google Map alternative as it's UI is the cleanest.
As someone else already said Magic Earth is great as a direct google maps alternative, I use it in combination with organic maps which I find better when on foot or looking around on the map.
Been using Magic Earth since its included within /e/OS on my phone. It's been fine for the most part. Sometimes it doesn't recognize the actual address but will get me at least on the street and from there can navigate myself