I love Agatha Christie books - they are relatively short but still seem to tell a good tale - and Hercule Poirot as a character, so it's always fun to pull one off the shelves and challenge my little grey cells. 
 It's always hard to talk about mysteries without giving away something vital. This story had a good cast of characters that seemed believable - not too quirky but each having enough of a personality to serve the story. The "whodunit" part of the story offered enough of a surprise to be fun - though I had my suspicions about halfway through! One of the better Poirot books, I think.