Well, as far as possible medical uses go, (I haven't read anything abour the product yet) does it have a stylus and handwriting recognition software? That could be useful, instead of having to type on a software keyboard, a doctor could simply use the stylus to write his notes, then have that automatically translated into an easily readable format and added to the patients charts/notes.
From a learning stand point, I could possibly see some use for one of these devices in a classroom environment. Being able to load textbooks onto it, perhaps have some kind of wireless system throughout a school that students would be able to log into with specific passwords for their classes to then get access to class notes, recorded lessons, and other useful classroom information. Though you could do this with a laptop as well, but this might be easier to carry around than a laptop.
Anyways, just some things I thought up for possible uses. I'm not a Mac fan, so I also see this as a large iPhone. Although if it has bluetooth, you could even start using it as a phone as well.