I've been using Apple Maps exclusively for a few years now, as I like the turn by turn directions much better, and the UI is more readable to me, as others have noted.

My wife seems to like Google Maps better, so we tried it on a recent trip. I ended up going around in circles in an unfamiliar area, and it kept telling me to turn where no road existed. I was flabbergasted it was so bad, as the last time I used it, I didn't remember it being so unreliable.