I need some help here.
The EPub, at one third the size, looks as good to me on the Sony as the PDF. The pictures look great, the tables look as good.
Apparently NASA knows how to do EPubs.
I would like to see input from others more familiar with what makes a good EPub on this platform; For me EPub is the one I will keep on the device - even though NASA says it is for the Nook.