Being low-vision I've listened to audiobooks from back in the days when it was dusty old men reading Nancy Drew on an old record player. It's amazing how much audiobooks have changed and how spoiled I've gotten. In many ways some of those old readers who did nothing but read did much less damage than some of the new readers who try to hard.
I very much enjoyed "The Beekeeper's Apprentice" on paper but have never been able to make it through Jenny Sterlin's incredibly forced audio rendition. I was able to make through Sally Darling's readings of Anne McCaffrey's Harper Hall trilogy but there was a bit of teeth-grinding because she reads so pompously.
I generally agree with other posters who have mentioned problems with authors reading their own works. I couldn't make it through the audiobook of "The Kite Runner" read by Khaled Hosseini but I was delighted when a new version came out read by Atossa Leoni.
For the most part, reading shouldn't be that hard. I'd strongly prefer that a reader simply READ a book cleanly than try to pump in lots of voices and accents unless they can do it as smoothly as Jim Dale and I've not heard anyone yet who can.
The producers have to take both credit and blame here as well. I utterly hate the addition of music and the weird pops, whistles, and clatters that are so often introduced as chapter changes, segment peices, and, in some cases, random noise. I wouldn't mind so much if these dischordant offerings were only BETWEEN the chapters but most of the time, they continue on over top of the reader for some time as he begins the chapter as well. For the most part, music, sound effects, and other accoustics distract from the reading as opposed to enhancing it unless handled with a very light hand.
There are some exceptional readers though. I'll listen to anything read by Scott Briggs (though Brick is good too) and I fell head-over-heels for Richard Matthews after listening to him read "The Count Of Monte Cristo". Frank Muller is also good.