I enjoyed the book thoroughly, but this may be somewhat biased as I love anything written by Agatha Christie. The book was easy to read, and finished comfortably within a day, so not too long. As another user has commented, there are a few aspects that seem a bit pointless towards the plot, but these were not too much of an issue.
I didn't feel it had the usual magic that the Poirot novels usually do, and I think you can definitely tell that it was one of the slightly later ones. There was a lot of comment throughout the novel on race, some of it which was a bit dodgy, but as with any Agatha Christie novel, you take it with a pinch of salt.