Having been an avid Sherlock Holmes fan, I finally decided to try reading some of the Poirot stories instead. This book was my first exposure to the Belgian detective, and to Agatha Christie's writing as a whole, and I have to say it has lived up to my hopes fairly well.
The writing style is very different to that of Doyle -- it feels very much more like 'classic' literature than the Holmes stories do... possibly a little more formal. For me, that made it a little less accessible, so I had to work a bit harder to get into the plots.
The mystery and intrigue are great though, and there's a splash of romance here and there. It takes you on a bit of an adventure of feelings about the main characters (Poirot and Hastings), as they portray very realistic development and personality traits.
My one criticism is that the plots tend to drag on a bit, so it is perhaps not ideal for people who prefer lots of pace. The third story ("The Big Four") is particularly bad for this... it just seems to go on and on... and then it suddenly stops in a slightly unsatisfactory way. It's still well worth reading it though.
I recommend this book as being an excellent introduction to the Poirot stories. If you are interested in crime stories and the somewhat bizarre methods of a small Belgian man, then you will be well catered for!