I like hardcover books better than soft cover books, eBooks, and audiobooks. A hardcover book reads differently, and the tactile nature of the book radically improves the experience. If I believe a book is important enough to read and study, I always buy it in multiple formats, as each one provides a different experience, and they build upon each other.
I read the hardcover book first, mostly because I seem to gain more from the first reading than when I read the Kindle or listen to the audiobook first (even though I sometimes listen to a book before reading it, mostly because I am traveling in a plane or a car, and because I can listen when I am doing something that doesn’t require my full attention). I tend to mark passages with a pencil, with a single dot at the beginning of an important passage, and another to mark the end. This note-taking device is mostly a habit that allowed me to type notes later and refer back to important ideas.
When I am far enough into the book, I like to start the audiobook and listen to what I have read, trailing behind my reading of the book. Hearing the concepts again is helpful. Going over the ground a second time deepens my understanding and my retention. I prefer books where the author reads their work, as they are almost always better than when someone else reads for them (with the exception of The Four Agreements by Don Miguel Ruiz, impeccably read by Peter Coyote, whose voices make the content even more powerful).
If I am reading to deepen my understanding, I read the book on Kindle or on the Kindle App on the iPad, highlighting and exporting the passages I want to respond to using a system called Zettlekasten, which is sort of like taking notes on index cards, with my notes on single ideas or passages captured electronically. The Kindle app allows you to copy the text directly into another program, in my case, the Ulysses app, which prevents meekest from having to type my notes, something that takes time better spent writing my notes and ideas and responses to what I have read.
Why go to all this trouble?
As I have written here before, there is no better deal on Earth when it comes to education than a book. For 6 hours and $25, you get access to ideas and insights from someone who invested tens of thousands of hours in attaining them.
At one time in my life, I read a book a day. For many years, I read a book a week, but with little to no application and too little retention. Now I prefer depth to breadth, reading widely until I find something worth studying, and then going very deep. If it takes a couple of weeks to draw out the marrow from the bone, the effort is worth the additional time and effort.