I've been using HERE for off-line navigation, and have had a lot of luck with it. As long as you offline the maps you need in advance, it does a great job for the turn-by-turn navigation, and actually has been successful in navigating forest service roads on Vancouver Island. Once offlined, it only requires a GPS signal for the turn-by-turn navigation. I'm from Canada, and I've used it offline in the U.S, France, Switzerland, Austria and Germany with great success without any data packages on my cell phone.
I also use Backcountry Navigator to track our travels. Again, saving the map offline in advance gives you the availability without data. This, combined with paper maps gives us a really solid combination for determining our routes off road.
I haven't tried Google's offline options yet, simply because the HERE app works so well. It's also nice to be able to log into HERE.com and plot points on a laptop/desktop, and have them sync to the phone.