I use the Navigation app that came with the TBolt. I believe it uses Google maps, but it just seems easier for me to use. I can just use speech to text to say the name of the restaurant, business, or address that I want to go to and it automatically finds it and gives me the turn by turn directions. So far it has been very accurate and also very fast to reroute if I decide to deviate. Plus it's free. I have never used Garmin, so I don't know how it compares, but I haven't felt the need to look for anything better.
One thing I thought was cool the first time I used it, was that when I arrived at my destination, it displayed a photo of it. Also, recently I was trying to go to a house address and I had the wrong address and the Navigation app took me to the right address anyway because the one I had didn't exist. Scary.