Like most people born in the last century I grew up reading print books. I never even thought of them as print books, that's just how they came.
Looking around at people's activities on my last flight a few weeks ago, and on my bus trips, people seem to be evenly divided between eReaders and print books, though I noticed on my last visit to Sydney that electronic devices outnumbered books, but they were also being used for texting/emailing and playing games, oh and maybe doing some work!
When travelling the majority of people are plugged into headphones (myself included). I listen to music, but also podcasts and audio books.
In addition to the obvious requirement of it being a good story, an audio book also needs a good voice. The last book I listened to was narrated by an actor I hadn't heard of, but he was excellent, especially in changing his voice for the dialogue sequences.
In contrast the person narrating the book I read before that irritated me immensely. The book was set in England and was about living in England, but the narrator was American - although I didn't hold that against him. Some well-known place names were (often) ridiculously pronounced, and if I hadn't been in public I would have shouted corrections at him. This was no cheap offering. It was a traditionally published book by a well-known author, and I would have expected a greater level of care.
On that thought I'll make a note to myself. When I'm famous enough to be able to choose someone to narrate my books I'll certainly check the finished product carefully, and I won't be narrating it myself. A couple of years ago, I had the opportunity to narrate part of a work in progress. I certainly wouldn't win any Oscar equivalents, but you can listen to it here if you're interested. The tag says it's from Ordinary Day (which was my working title for Lives Interrupted), but it's actually from an unpublished novel, still untitled!