In terms of large controls
Generally I think the iPod Touch is best at granting a large 'footprint' to control surfaces. Yes it's touchscreen and lacks any sort of haptic/mechanical feedback, but its screen is large and generally its onscreen choices are reasonably easy to read. I may not be in a retirement home, but I'm definitely challenged with my near-sight vision, and I've yet to have any visual clarity issues with my Touch. Plus it's Audible compatible.
Now as to how easy it is to manage and download...well, someone else will have to attest to that. I still do books the old-fashioned, traditional way.