Instant borrowing of not just books, but also movies, music, and comics with no "holds" queue. 2. Personal Cataloging Apps (Home Library)

Seamless synchronization across devices. You can start a book on your Android phone and pick up where you left off on a tablet or web browser.

Offers immediate access without waitlists for many titles.

Depending on your goal, the "solid features" differ significantly:

These apps are designed to help you keep track of the physical books you already own. Libby, the library app - App Store - Apple