What are your views on them? Is it just cheating, or a great way to bring literature alive? Personally I couldn't live without them, but I find they work best with lighter novels, particularly Waugh's comic novels (Decline and Fall, Vile Bodies, Sword of Honour trilogy), P G Wodehouse, Kingsley Amis etc or with writers who had a simple prose style like Hemingway.
They are also great for people like Joyce, Chaucer, Shakespeare etc so long as you read them first THEN listen to them. The RSC (Royal Shakespeare Company) actor Paul Scofield once did a reading of The Wasteland which I have- no matter how many times I read that poem I wouldn't get as much out of it as I do listening to that recording. The same goes for a magnificent recording I have of Blake's Songs of Innocence and Waugh's Decline and Fall. I could read that novel over and over and I wouldn't enjoy it as much as the audio version.