Mostly I love listening to different accents, though I have run into a very few over the years that I could not understand well enough to follow the story, which makes me sad. :-(

The only thing I don't really enjoy involving accents is when the reader tries to simulate one that isn't their own and doesn't do it well, which tends to pull me out of the story. Not, mind you, that I'm trying to discourage readers from attempting accents other than their own; some people do them very well indeed!

I think what it boils down to is that I like to listen to people reading/telling me stories, and a reader's accent is much more likely to enhance my enjoyment of a podfic than not.