It takes a special kind of narrator to make an audiobook by Mark Twain almost boring, but Robin Field nearly manages it. To be fair, some of his voice characterizations when doing dialogue are quite good, but his straight narration is pretty dull. Still, Twain's writing is generally good enough that once you get accommodated to the lackluster reading after a couple of stories or so, you're able to just enjoy it on the strength of its own merits.
Included here are some of the standard stories that are in practically every Twain collection, like "Jim Smiley and His Jumping Frog" and "Extracts from Adam's Diary" and "Eve's Diary", and some moderately well-known gems like "Punch, Brothers, Punch!" and "The Story of the Bad Little Boy Who Didn't Come to Grief"---but also a few that I had never encountered before, including the excellent "The Man That Corrupted Hadleyburg", a longer work that takes on some pretty serious themes, among others that untried virtue is not real virtue and ill-gotten gains are not gains at all.
So I give the collection of stories four and a half stars, but the narration only two and a half, for three and a half overall. I recommend either not getting the audio edition, or looking for another collection with a different reader.