I have a strong preference for the Samsung model we already have, so I was delighted to find several of them, cheaply won, on Ebay. The first one will arrive soon, so I will be able to see how good Ebay stuff is with equipment that us familiar to me. And I will be able to put them in waterproof cases available locally. If they are really good I will save one as a personal backup for car use, and keep it dry and unfrozen. The rest will rotate as water units for students.
It's actually an advantage to my planned use of these that copying music off of IPods is a no-no, but on the Samsungs it's a snap.