Has some great features, including different ways to sort your lists of read, want to read, and currently reading. I use the app primarily for those 3 lists.
I also appreciate the book ratings and reader reviews. It helps me determine whether to read a book or not, or purchase vs. check out from the library (I never feel bad returning a partially read book to the library, but hate not finishing one Ive bought).
However, I think I would use the app more if it could improve in the suggestions based on my reading lists. Right now selections seem somewhat random, and the same titles repeatedly show up when I search categories for new things to read. I started using Goodreads with the hope of finding new books to interest me, and it does that sometimes. I just wish it did so successfully more often.