This is the episode that started it all. And while it's good and is accurate to what future episodes would bring, it could have been better.
David Suchet is good as Poirot, but not great. But who can expect him to be? It is the first episode, and the character would develop a lot further in later episodes. "The walk" is not there, and Poirot smiles with his teeth visible, which if you look at later seasons, he never does. But I'm not blaming him at all. His performance is still fantastic.
Hastings, Japp, and Miss Lemon add to the fun. Hastings has many funny moments. It's always amusing to see him trying to catch up with Poirot and being left in the dark. Hugh Fraser, Philip Jackson, and Pauline Moran are all teriffic.
But the episode has a few flaws. I found the Scottish maid Annie annoying, as I could barely hear a word she said. The accent was far too thick. Also, Hastings makes a quick remark in the beginning about a bank, and later suddenly Poirot and Hastings are talking about the same bank and its importance. They keep talking about a man named "Davis" and I had no idea who he was. Only on watching it again could I comphrehend it, and even then I felt that not everything was made clear.
Still, it is a good episode, and I enjoyed it.