Tortoise

Depends what you are wanting. If you are just wanting something to comply with R licence requirements then a phone with Avenza works great. Just make sure of battery life by turning the phone off or putting it in flight mode when not in use. Alternatively carry a power bank. If you're relying on the GPS for critical navigation then consider a specific device (better battery life and sometimes more precise location and functionality). That said, I'm not comfortable relying on a battery powered device when navigation is critical to my well-being. A map and compass and the skill to use them is well worth obtaining.