I read around 60 books a year (it'll be 70+ this year), mostly fiction, some history, a dash of other things. About half of those are audio books these days. They don't replace reading for me, but supplement it. I can listen to audio at times when I can't read. This happens most successfully when I'm doing the dishes, gardening, or when working in CAD at work if the work is purely spatial. Long highway drives also work for me, but not so much for city driving, in which case I prefer the radio anyway. I also listen when walking to work in the winter, sometimes with mixed success, or when I wake up at 5:00am but am not ready to actually get up - I can listen with good focus for an hour or more.
I've definitely improved since I started.
In a few cases I've felt the audio experience probably enhanced my enjoyment of the book. One of these was Josh Mallerman's Bird Box (soon to be on Netflix, if you're wondering why it sounds familiar). The story is told as a first person narrative, and having someone read that to your ears sounds personal and intimate. That story is a horror/thriller in which characters must go about blindfolded, and it turns out that audio does wonders for this because you can read with your eyes closed, imagining what the character does as she describes sounds and tactile experiences.
Some performers can really enhance the experience, too. The Richard Sharpe series by Bernard Cornwell, for example, is really wonderfully narrated - no, performed - so it's more like listening to an audio play.
Where I really prefer a book is when the writing has depth, or information I want to remember. I just listened to Joseph Campbell's Hero With a Thousand Faces and now definitely want to read it. This is because the book is so full of ideas that I want to keep notes and excerpts - I can't do that in most cases when I'm listening. It's also rather dense in places, and reading helps in comprehension, and it's easier to back up a paragraph to read it again. Another example would be Moby Dick - I can't imagine getting as much out of that listening as I do reading.
Sometimes, when the narrator just doesn't have the same perspective on a book that you would, the audio format can interfere with your enjoyment. Luckily with Audible you can return books that didn't work out for you.