Depending on your goal, the "solid features" differ significantly:
Offers immediate access without waitlists for many titles. Library Book App Android
These apps are designed to help you keep track of the physical books you already own. Libby, the library app - App Store - Apple Depending on your goal, the "solid features" differ
These apps connect to your local library card so you can borrow ebooks and audiobooks for free. Depending on your goal
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.