This was a very satisfying murder mystery. The clues were cleverly dropped in ways that I didn't notice at the time but largely seem obvious in hindsight. 

The structure of the book is interesting, with each of the five individuals involved first being interviewed by Poirot and then sending him a narrative describing their recollections. This did unfortunately lead to a fair amount of repetition, which is my one significant criticism of the book. Overall though I enjoyed this quite a bit.