I think the best option is a Garmin, specifically something like the eTrex Legend HCx or maybe one of the Dakota or Oregon range. They are reasonably small, plus rugged and with decent battery life, so good for hiking.

You can convert OSM maps to load on them, plus there’s a variety of ready made maps to download.
They work as standard USB mass storage devices, so its easy to load maps or download tracks using Linux etc.

For decent commercial maps, with hiking trails - it depends on where in the world you are. Some countries have pretty good commercial Garmin maps with paths etc, others its just street maps. And in some places OSM maps are more useful than the official / commercial Garmin maps.