Absolutely nothing against dedicated GPS units however I choose to use either my iPhone or iPad and pair it with a
Bad Elf GPS Pro via bluetooth. This provides much better GPS accuracy and has excellent battery life. Additional benefits are that by not running the GPS on my smartphone the battery lasts much longer there as well plus I don't have to keep my phone where it has a clear view of the sky.
I do a lot of off road driving so with this setup I simply use a different app for mapping and tracking trails verses on road turn-by-turn navigation. In my rig I typically use the iPad for the larger display and off road my iPhone for compact portability.