Collectorz software is a godsend to anyone who collects books. They also have versions that work for movies, albums, comics and games. I've been using their book software since 2007. It's easy to use and keeps track flawlessly.
There is no affiliate program and I've never seen any advertisements. The product speaks for itself. Thanks to their software, I know exactly what books I have, what books I want, and what books I have already read. I know when I got a book, when I read a book, and what series it goes with. You even get free web space so you can share your collection -- here's mine!!
I own the iPad, Android, and PC versions. No matter where I am, my book collection is at my fingertips. Priceless.