Tablet for my mother.

To keep it short, my mom is a Airline Captain and she has to carry around these big heavy manuals everywhere she goes, so I need to find the perfect tablet to view all her manuals in PDF form. Right now all I really have in consideration is the Nexus 10 because of its screen res and battery life, and the ipad also because of its screen res and its simplicity to use. Thank you guys for any help you can give me!