imo a tablet is probably the most versatile setup. can find the best maps for your region and load them with onx, vvmapping, lifetime trail maps, ride command, avenza (for any forest service maps), etc. plus you can run music and such as well with it.
garmin is my other choice, anything from a nuvi to a tread will work depending on your needs and maps. the tread seems like a great setup with some ram mounts.
steve